Not sure what OS you're running (assuming it's Vista or 7). right click on the shortcut > click properties and in the target line add:
C:\Windows\System32\cmd.exe /C start /affinity 1 Blood2.exe
or open Task Manager after you loaded the game > Processes tab > right click on either Blood2.exe or Client.exe > click "Set Affinity" and uncheck one of the boxes, doesn't matter which box.

Well heres what happened to me. I first went to the task manager ect ect. However, there was already only one box checked. I then remembered that gog apparently set Blood 2 up for windows xp compatability mode. I turned it back from windows 95 to windows xp and somehow i was able to join again. However when I tried to change my resolution from 640x480 to 800x640 the game got the error again. But then i turned it onto one core affinity and somehow I was able to play a single player game. However when I got off the game it got the error. I guess this means ill only be able to play in 640x480. Oh well, see yall on if youd like to play. I might record some footage :D. BTW http://www.penny-arcade.com/comic/1998/12/21/ . Cant wait till gog fixes this! Its gunna be awesome!
ARGH. Atleast i thought it was working. Right when I saw you on ILive. Trying to join again....
Nope not working. Sorry guys. I wish I would be able to play.

Wierd. I was able to run the game in the highest resolution but it suddenly got the error. Anyways good game. Will get this problem fixed asap. Atleast i got to play for awhile. I will probably be able to play again.

Server crashed when the 3 of us were playing there. Wonderful MFC error. Back up and running though.

Seemed like it was very smooth on the Cradle to Grave map before I had to run.