I encountered a similar or identical problem. I too had Firefox 2.0 and Gaim 2.0.0beta3.1 running. In my case, I was modifying my preferences in Gaim when the "mono crash" error appeared.
Running Ubuntu 6.10 (Final)... ** Attachment added: "mono.1000.crash log" http://librarian.launchpad.net/4964754/_usr_bin_mono.1000.crash -- mono crash while surfing with firefox 2.0 https://launchpad.net/bugs/69164 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs