I found this workaround while adventuring through Google for what appear to be the entirely random crashes in Fall of the Samurai that some users have experienced:

http://www.twcenter.net/forums/showthread.php?t=238484

While the thread says that it is for E:TW, the workaround is apparently relevant even to this game as described in this thread on the official Total War forums:

http://forums.totalwar.com/showthrea...bit-workaround

Prior to using this fix, I experienced the same kind of random errors described by the poster in the linked thread. These appear to have gone away completely by going through the steps in the workaround.

Hope it helps for you!