I think I've seen only 4 or 5 corrupt turns out of ... 2000 or 3000 turns. Two or three of those were on the same machine, which turned out to have problems.
This makes me suspect that you have a problem with your system - probably either bad memory, or corrupt / bad hard drive / interface. Recommend downloading and running diagnostics for memory and HD especially, and completely defragmenting the hard drive.
Of course - it could also simply be Windows XP.
Edit: Also, when hosting / playing on the same machine, I think the most common error is that the _game_ will crash, saying Nagot Glick Fell or some such, and reporting that it couldn't open a temp file (due to the other instance of Dom2 having it open already). Then again - WinXP may not be locking the file properly, thus allowing both to write at the same time.
But again - you get 1 in 20 corrupt even using a separate machine. It's gotta be your system - bad memory, corrupt OS, virus, bad install of Dom2, something.