I've seen this problem with quite a few mods. I assume it's some rare set of world gen circumstances (perhaps, say, a wereperson giving birth? except that one was fixed) that doesn't happen in vanilla. It's a hassle to use a mod that has this problem, because world gen is always a crap shoot: OK I got an alright world...do I go for 1000 years of history to ensure lots of interesting stuff? Or do I only try for 250 because I'm afraid it will crash before it gets to 500?
One question I didn't research yet: if you run the same world gen starting from the same seed twice, does it crash on the same year? If so then it seems like it should be possible to upload all the mod files plus the seeds (or a whole DF installation with everything in place), and then the devs should be able to catch it happening in the debugger and fix it.
A few things come to mind that could be done with the code that would help with these situations:
*
This thread's suggestion, resuming world history generation. So we could save our world with 0 years of history at first, then reload it and generate only 100 years at a time. That way if it crashes on year 467, at least I have 400 years of history to start my fort.
* Date stamp messages to the error log during world gen. Maybe a line for each year (or decade), so we can tell (within a few years) when the crash happened.
* I guess we could log some random events to the game log during world gen, but we'd have to get lucky to log the actual one causing the crash. Still might be worth adding a few random ones just to be able to orient yourself looking through the logs.