Diablo 2 Error

Ok heres the deal...
I get this error (see below) Every now and then.
It strange, cause i'll get in a room, go to another
wp to do my warcry, and as the gate is opening
*DINK, i get thaht error. Then after i get that
error i can join nor create any games, till i restart my computer. But i know its nothing to do with my char,
cause right i get the error, i'll try to get on with my other computer and it works fine. (and my other computer
has less memory) any suggestions?