From the Aedui CTD thread:

Quote Originally Posted by Tretii
In fact I had nothing but problems with Aedui. BUT! Before I kept donwloading
0.8 and 0.81 separately. Then I got fed up with constant ctds and decided to download the whole new 0.81 (0.8 already included)
Tried that, and voila, no CTDs whatsoever. Try that, if you already didn't.
So there are a number of possibilities here:
1) The Full install is somewhat different from 0.8 + 0.8.1 patch
2) CTD experiences are due to corrupted downloads

Thus, it would be worth the effort to list what EB 0.8.1 you're using when you experience a CTD during the AI's turn.