It happens on x86 too. It usually happens when another notification balloon is visible. I think it's gaim's notification icon code that crashes rather than the main code. It is pretty common crash.
-- [apport] gaim crashed with SIGSEGV in g_cclosure_marshal_VOID__VOID() https://launchpad.net/bugs/89262 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs