http://bugs.winehq.org/show_bug.cgi?id=20046
--- Comment #2 from Henri Verbeet hverbeet@gmail.com 2009-09-14 08:54:34 --- (In reply to comment #0)
xp_destroy_surface: assertion failed: s != ((void *)0) xp_destroy_surface error: 3
That's from XQuartz, not Wine. I know we've fixed races like that in the crossover X server, and I wouldn't be surprised if this one is the cause for the issues you're seeing.