Using AutoCAD 2011 on Windows XP, you may get this error unexpectedly:
FATAL ERROR: Unhandled e0434f4dh Exception at 7c812afbh
In this case, the problem occured with only 1 login on the computer. The fastest solution was to delete the user’s Windows profile (for Windows XP, it is in Documents & Settings) and this has resolved the issue.
Thanks to Michael Kane for this awesome tip.