Same problem here:

* ThinkPad T43p
* multiple routers tested - bug is "always" there, just frequency of occurrence changes
* # uname -a
  Linux XXX 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12 05:23:09 UTC 2010 i686 GNU/Linux
* # cat /etc/lsb-release | tail -1
  DISTRIB_DESCRIPTION="Ubuntu 9.10
* # lspci | grep -i Net
  02:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5751M Gigabit Ethernet PCI Express (rev 11)
  0b:02.0 Network controller: Intel Corporation PRO/Wireless 2200BG [Calexico2] Network Connection (rev 05)
* # uptime; dmesg | grep "ipw2200: Firmware error detected.  Restarting." | wc -l
  20:05:55 up 1 day,  9:06,  4 users,  load average: 0.02, 0.14, 0.16
  59
* # modinfo ipw2200
  filename:       /lib/modules/2.6.31-20-generic/kernel/drivers/net/wireless/ipw2x00/ipw2200.ko
  [...]
  version:        1.2.2kmprq
  description:    Intel(R) PRO/Wireless 2200/2915 Network Driver
  srcversion:     99130395C362697D0971661
  [...]
  vermagic:       2.6.31-20-generic SMP mod_unload modversions 586 
  parm:           disable:manually disable the radio (default 0 [radio on]) (int)
  parm:           associate:auto associate when scanning (default off) (int)
  parm:           auto_create:auto create adhoc network (default on) (int)
  parm:           led:enable led control on some systems (default 1 on) (int)
  parm:           debug:debug output mask (int)
  parm:           channel:channel to limit associate to (default 0 [ANY]) (int)
  parm:           rtap_iface:create the rtap interface (1 - create, default 0) (int)
  parm:           qos_enable:enable all QoS functionalitis (int)
  parm:           qos_burst_enable:enable QoS burst mode (int)
  parm:           qos_no_ack_mask:mask Tx_Queue to no ack (int)
  parm:           burst_duration_CCK:set CCK burst value (int)
  parm:           burst_duration_OFDM:set OFDM burst value (int)
  parm:           mode:network mode (0=BSS,1=IBSS,2=Monitor) (int)
  parm:           bt_coexist:enable bluetooth coexistence (default off) (int)
  parm:           hwcrypto:enable hardware crypto (default off) (int)
  parm:           cmdlog:allocate a ring buffer for logging firmware commands (int)
  parm:           roaming:enable roaming support (default on) (int)
  parm:           antenna:select antenna 1=Main, 3=Aux, default 0 [both], 2=slow_diversity [...]
* # ifconfig eth1
  eth1      Link encap:Ethernet  HWaddr XX:XX:XX:XX:XX:XX  
          inet addr:10.XX.XX.XX  Bcast:10.XX.XX.255  Mask:255.255.254.0
          inet6 addr: XX::XX:XX:XX:XX/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:353364 errors:4 dropped:4 overruns:0 frame:0
          TX packets:353521 errors:0 dropped:3 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:356051366 (356.0 MB)  TX bytes:169257557 (169.2 MB)
          Interrupt:21 Base address:0xe000 Memory:b4001000-b4001fff
* # iwconfig eth1
  eth1      IEEE 802.11g  ESSID:"XXX"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: XX:XX:XX:XX:XX:XX   
          Bit Rate:54 Mb/s   Tx-Power=20 dBm   Sensitivity=8/0  
          Retry limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=77/100  Signal level=-52 dBm  Noise level=-89 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:6