Hi, it's the same bug?
The libcanberra error is related to https://bugs.launchpad.net/ubuntu/+source/ia32-libs/+bug/369498

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed


$ firefox
Gtk-Message: Failed to load module "canberra-gtk-module": /usr/lib/gtk-2.0/modules/libcanberra-gtk-module.so: classe ELF errata: ELFCLASS64
NPP_New called
DBUS connection created
Listening to path /control/16915
ARG: src = http://static.ak.fbcdn.net/sound/pop.mp3
ARG: autostart = true
ARG: loop = false
ARG: hidden = true
New Stream Requested
opening /home/tyrael/.cache/gnome-mplayer/plugin/gecko-mediaplayertaudde.mp3 for localcache
Entering destroy stream reason = 0 for http://static.ak.fbcdn.net/sound/pop.mp3
Entering list_parse_qt localsize = 625
unable to find rmda in /home/tyrael/.cache/gnome-mplayer/plugin/gecko-mediaplayertaudde.mp3
Entering list_parse_asx localsize = 625
Item 
src = http://static.ak.fbcdn.net/sound/pop.mp3
local = /home/tyrael/.cache/gnome-mplayer/plugin/gecko-mediaplayertaudde.mp3
id = 1
play = 1
path = 
controlid = 0
playerready = 0
newwindow = 0
cancelled = 0
streaming = 0
loop = 0
loopcount = 0
Exiting list_parse_asx
Entering list_parse_qml localsize = 625
Item 
src = http://static.ak.fbcdn.net/sound/pop.mp3
local = /home/tyrael/.cache/gnome-mplayer/plugin/gecko-mediaplayertaudde.mp3
id = 1
play = 1
path = 
controlid = 0
playerready = 0
newwindow = 0
cancelled = 0
streaming = 0
loop = 0
loopcount = 0
Exiting list_parse_qml
URL Notify http://static.ak.fbcdn.net/sound/pop.mp3
,0 = 0
http://static.ak.fbcdn.net/sound/pop.mp3
/home/tyrael/.cache/gnome-mplayer/plugin/gecko-mediaplayertaudde.mp3
/control/16915
New Stream Requested
item is null
stream url http://static.ak.fbcdn.net/sound/pop.mp3
Entering destroy stream reason = 1 for http://static.ak.fbcdn.net/sound/pop.mp3
Exiting destroy stream reason = 1 for http://static.ak.fbcdn.net/sound/pop.mp3

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed

(firefox:3864): Gdk-CRITICAL **: gdk_x11_xatom_to_atom_for_display: assertion `xatom != None' failed
*** NSPlugin Viewer  *** ERROR: NPN_InvalidateRect() invoke: Connessione interrotta dal corrispondente
Segmentation fault (core dumped)


I have a Zotac ION motherboard with ATOM N330 and Karmic AMD64

$ lspci
00:00.0 Host bridge: nVidia Corporation MCP79 Host Bridge (rev b1)
00:00.1 RAM memory: nVidia Corporation MCP79 Memory Controller (rev b1)
00:03.0 ISA bridge: nVidia Corporation MCP79 LPC Bridge (rev b2)
00:03.1 RAM memory: nVidia Corporation MCP79 Memory Controller (rev b1)
00:03.2 SMBus: nVidia Corporation MCP79 SMBus (rev b1)
00:03.3 RAM memory: nVidia Corporation MCP79 Memory Controller (rev b1)
00:03.5 Co-processor: nVidia Corporation MCP79 Co-processor (rev b1)
00:04.0 USB Controller: nVidia Corporation MCP79 OHCI USB 1.1 Controller (rev b1)
00:04.1 USB Controller: nVidia Corporation MCP79 EHCI USB 2.0 Controller (rev b1)
00:06.0 USB Controller: nVidia Corporation MCP79 OHCI USB 1.1 Controller (rev b1)
00:06.1 USB Controller: nVidia Corporation MCP79 EHCI USB 2.0 Controller (rev b1)
00:08.0 Audio device: nVidia Corporation MCP79 High Definition Audio (rev b1)
00:09.0 PCI bridge: nVidia Corporation MCP79 PCI Bridge (rev b1)
00:0a.0 Ethernet controller: nVidia Corporation MCP79 Ethernet (rev b1)
00:0b.0 IDE interface: nVidia Corporation MCP79 SATA Controller (rev b1)
00:0c.0 PCI bridge: nVidia Corporation MCP79 PCI Express Bridge (rev b1)
00:10.0 PCI bridge: nVidia Corporation MCP79 PCI Express Bridge (rev b1)
00:15.0 PCI bridge: nVidia Corporation MCP79 PCI Express Bridge (rev b1)
00:16.0 PCI bridge: nVidia Corporation MCP79 PCI Express Bridge (rev b1)
00:17.0 PCI bridge: nVidia Corporation MCP79 PCI Express Bridge (rev b1)
00:18.0 PCI bridge: nVidia Corporation MCP79 PCI Express Bridge (rev b1)
03:00.0 VGA compatible controller: nVidia Corporation ION VGA (rev b1)
04:00.0 Network controller: Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-Express) (rev 01)