It's also affecting one of my bugs: http://bugs.winehq.org/show_bug.cgi?id=15858
It's sort of random when a real crash occurs but the debugging revealed that the object that is used was already freed by wined3d.
I can increase the probability of a crash by running a bunch of memory-hungry apps besides wine. Loading a level mostly works when there isn't much memory-load on the system. Possibly other apps overwrite the memory that was previously freed. Of course this doesn't happen so often when there are only a few apps actually using mem.
I strongly encourage a proper fix, since the current situation is... well, sorta ugly (it works, but having random crashes on level load isn't exactly smooth gameplay...)
Greets, Tobias