It appears this was related to a bug encountered while using Gaim (https://launchpad.net/bugs/74631) as it hasn't happened again since that issue got fixed (computer has been running almost non-stop since the original report).
-- Applications refuse to start https://launchpad.net/bugs/74731 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs