Sleuthing X windows bug in Ubuntu Gutsy

version number:    11.0
vendor string:    The X.Org Foundation
vendor release number:    10400090
X.Org version: 1.4.0.90

Sigh. Debugging X is such a pain...

Just a suggestion, but have you tried it with an Xnest, or an Xvfb 
server? That way it should only crash that server and not the one you 
are working on.

Barry