[Crash 0.77] Screen goes black but game doesn't CTD

Playing on my old desktop about every 10-15 mins the game goes completely black.  The music continues to play and the cursor stays as the sword.  No one event seems to trigger it.  It happened on end turn, end of battle and clicking to move.  The task manager still says that the game is running and I have to force quit to exit.  The zip files were created after I force quit, not when the screen turned black.

Crash 1:

http://dl.dropbox.com/u/20243425/Crash/1/debug.err

Crash 2:

http://dl.dropbox.com/u/20243425/Crash/2/debug.err

http://dl.dropbox.com/u/20243425/Crash/2/FallenEnchantress0_77-2012-02-01T22-19-41-161.zip

Crash 3:

http://dl.dropbox.com/u/20243425/Crash/3/debug.err

http://dl.dropbox.com/u/20243425/Crash/3/FallenEnchantress0_77-2012-02-01T22-39-18-913.zip