flipping pixmaps in buttons

["Fiorillo.Paul" <Paul Fiorillo IGT com>]

Hello - I'm having a little difficulty flipping a pixmap image within a
button from the callback function called when I emit a "pressed" signal.  An
image already exists in the button before I try to flip the depressed
version in.  I get a 

Gdk-ERROR **: Fatal IO error 0 (Success) on X server :0.0

I also get an Xlib: unexpected async reply (sequence 0x19e)!

It's a little cornfusing.  Any hints on what I may be doing wrong?

Thanks for the help.

Paul Fiorillo