You don't give any information about your league, which is always helpful when asking questions. From what I can see, though, this problem has been usually encountered when using a modded quickstart or template.
For example, this thread was from somebody using a quickstart:
http://www.ootpdevelopments.com/boar...available.html
This one was from somebody using Skydog's template, and he got a suggestion on how to fix it:
Any suggestions?
Interestingly, the same guy posted the problem in here (#71) and rejoiced when it was resolved (#81):
SkyDog OOTP2K7 Fictional League Settings, v1.0
WOB 2.0 also reported it (Hmmm, they mention a Hawaii League in there. Is this the quickstart that you are playing?):
http://www.ootpdevelopments.com/boar...on-thread.html
And in this thread, bp_, the maker of the quickstart in the first thread, announces that he has fixed the problem:
http://www.ootpdevelopments.com/boar...689-crash.html
None of this may be helpful to you, unfortunately. However, if it is a modded quickstart or template that you are using, it may help to download it again to get the latest version, or merely to restart the one that you have. Hopefully somebody else will have more to add here.