Hi! 

I send more detail. If I use nm-applet 0.6.5 (gnome) instead of knetworkmanager (kde), the error occurs rarer.
Now the AP was disconnected after one hours, and it was impossible to reconnect.
Here is the syslog.

Apr  3 22:34:34 emerald kernel: [ 3245.089841] phy0 -> rt73usb_rf_write: Error - PHY_CSR4 register busy. Write failed.
Apr  3 22:34:34 emerald kernel: [ 3245.095357] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x3024 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095373] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3024 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095386] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x3020 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095400] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3020 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095413] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x3040 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095427] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3040 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095440] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x3050 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095453] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3050 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095467] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x3064 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095480] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3064 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095495] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x3040 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095508] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3040 with error -19.
Apr  3 22:34:34 emerald kernel: [ 3245.095576] wlan0: No STA entry for own AP 00:18:f3:4d:c1:8d
Apr  3 22:34:35 emerald kernel: [ 3246.094920] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.094954] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.094968] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.094984] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x30c4 with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.094998] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.095111] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.095224] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.095336] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.095449] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:35 emerald kernel: [ 3246.095560] phy0 -> rt73usb_bbp_write: Error - PHY_CSR3 register busy. Write failed.
Apr  3 22:34:36 emerald NetworkManager: <info>  wlan0: link timed out.
Apr  3 22:34:36 emerald NetworkManager: <info>  SWITCH: found better connection 'wlan0/Sarpeidon' than current connection 'wlan0/Sarpeidon'.  same_ssid=1, have_link=0
Apr  3 22:34:36 emerald NetworkManager: <info>  Will activate connection 'wlan0/Sarpeidon'.
Apr  3 22:34:36 emerald NetworkManager: <info>  Device wlan0 activation scheduled...
Apr  3 22:34:36 emerald NetworkManager: <info>  Deactivating device wlan0.
Apr  3 22:34:36 emerald dhclient: There is already a pid file /var/run/dhclient.wlan0.pid with pid 6004
Apr  3 22:34:36 emerald dhclient: killed old client process, removed PID file
Apr  3 22:34:36 emerald kernel: [ 3247.094295] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094329] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094343] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094359] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x30c4 with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094372] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094485] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094598] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094710] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094823] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:36 emerald kernel: [ 3247.094934] phy0 -> rt73usb_bbp_write: Error - PHY_CSR3 register busy. Write failed.
Apr  3 22:34:36 emerald dhclient: wmaster0: unknown hardware address type 801
Apr  3 22:34:36 emerald dhclient: wmaster0: unknown hardware address type 801
Apr  3 22:34:36 emerald dhclient: DHCPRELEASE on wlan0 to 192.168.1.1 port 67
Apr  3 22:34:37 emerald avahi-daemon[5243]: Withdrawing address record for 192.168.1.3 on wlan0.
Apr  3 22:34:37 emerald avahi-daemon[5243]: Leaving mDNS multicast group on interface wlan0.IPv4 with address 192.168.1.3.
Apr  3 22:34:37 emerald avahi-daemon[5243]: Interface wlan0.IPv4 no longer relevant for mDNS.
Apr  3 22:34:37 emerald NetworkManager: <info>  Activation (wlan0) started...
Apr  3 22:34:37 emerald NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) scheduled...
Apr  3 22:34:37 emerald NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) started...
Apr  3 22:34:37 emerald NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) scheduled...
Apr  3 22:34:37 emerald NetworkManager: <info>  Activation (wlan0) Stage 1 of 5 (Device Prepare) complete.
Apr  3 22:34:37 emerald NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) starting...
Apr  3 22:34:37 emerald NetworkManager: <info>  Activation (wlan0/wireless): access point 'Sarpeidon' is encrypted, and a key exists.  No new key needed.
Apr  3 22:34:37 emerald NetworkManager: <info>  DHCP daemon state is now 14 (normal exit) for interface wlan0
Apr  3 22:34:37 emerald kernel: [ 3248.093752] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.093785] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.093799] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.093814] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x30c4 with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.093828] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.093941] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.094054] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.094166] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.094279] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:37 emerald kernel: [ 3248.094390] phy0 -> rt73usb_bbp_write: Error - PHY_CSR3 register busy. Write failed.
Apr  3 22:34:37 emerald NetworkManager: <info>  DHCP daemon state is now 11 (unknown) for interface wlan0
Apr  3 22:34:37 emerald NetworkManager: <info>  DHCP daemon state is now 14 (normal exit) for interface wlan0
Apr  3 22:34:38 emerald NetworkManager: <info>  supplicant_interface_init() - connect to global ctrl socket (0/10).
Apr  3 22:34:38 emerald kernel: [ 3249.093292] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093327] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093342] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093357] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x30c4 with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093371] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093484] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093596] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093709] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093822] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x308c with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.093933] phy0 -> rt73usb_bbp_write: Error - PHY_CSR3 register busy. Write failed.
Apr  3 22:34:38 emerald NetworkManager: <info>  supplicant_interface_init() - connect to global ctrl socket (1/10).
Apr  3 22:34:38 emerald kernel: [ 3249.138977] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3010 with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.169595] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x3040 with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.169628] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3040 with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.169643] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x0a failed for offset 0x0000 with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.169657] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3028 with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.169670] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x3064 with error -19.
Apr  3 22:34:38 emerald kernel: [ 3249.169684] phy0 -> rt2x00usb_vendor_request: Error - Vendor Request 0x0c failed for offset 0x0000 with error -19.
Apr  3 22:34:38 emerald NetworkManager: <info>  supplicant_interface_init() - connect to global ctrl socket (2/10).
Apr  3 22:34:38 emerald NetworkManager: <info>  SUP: sending command 'INTERFACE_ADD wlan0^I^Iwext^I/var/run/wpa_supplicant5^I'
Apr  3 22:34:50 emerald NetworkManager: <info>  SUP: response was 'TIMEOUT[CLI]'
Apr  3 22:34:50 emerald NetworkManager: <WARN>  nm_utils_supplicant_request_with_check(): supplicant_interface_init: supplicant error for 'INTERFACE_ADD wlan0^I^Iwext^I/var/run/wpa_supplicant5^I'.  Response: 'TIMEOUT[CLI]'
Apr  3 22:34:50 emerald NetworkManager: <WARN>  real_act_stage2_config(): Activation (wlan0/wireless): couldn't connect to the supplicant.
Apr  3 22:34:50 emerald NetworkManager: <info>  Activation (wlan0) failure scheduled...
Apr  3 22:34:50 emerald NetworkManager: <info>  Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
Apr  3 22:34:51 emerald NetworkManager: <info>  Activation (wlan0) failed for access point (Sarpeidon)
Apr  3 22:34:51 emerald NetworkManager: <info>  Activation (wlan0) failed.
Apr  3 22:34:51 emerald NetworkManager: <info>  Deactivating device wlan0.


Now I will upgrade to hardy, I will report it...