[CRASH] Long Game; CTD When "Returning Focus"

Playing the game in Windowed mode, I was moving back and forth between Elemental, Pidgin, Firefox, etc. freely for about an hour total, playing the game deep in and conquering most of my enemies. . .

And then, suddenly, I tab back over to Elemental, hit the next turn button, and the music skips for a half-second, then the entire program just unloads sans error message.  My debug.err is huge, of course, given the length of the game, but the end specifies a bunch of things not unloaded properly from memory.  It's located in the pastebin link above.

Cool first game, but I wish I had any idea what the hell I was doing so that I hadn't spent the entire game with negative income unable to build buildings in a reasonable fashion.