Note that this patch will not work if you have a DVD copy of the game, or downloaded it (legally) from D2D. You'll have to wait for the Critical Rebuild files to be posted up on Obsidian's site, which was supposed to happen on Wed pm Pacific time (I checked just not and it wasn't there yet).
Apparently the SP game should work ok without the patch.
More details
HERE.
[ 11-02-2006, 02:33 AM: Message edited by: Memnoch ]