I wouldn't really call it a "Vista 64" issue. Sure he had the same OS and you both get the same error. But lets throw a wrench in the mix ..
Im 64bit vista and i host majority of my games ... this week it did it once randomly and after that hasn't since. Actually come to think of it i host 99% of my demigod games because my friends would rather me then them ... /shrug.
I'm not sure of the issue or how to fix it ... maybe compatibilty mode like that one guy said? Maybe that would work? But as for now i haven't done that or anything and i run just fine. Window mode to actually.
Come to think of it .. WAIT A TIC ... Do you guys minimize your game alot? IF SO THATS WHY!. Minimizing this game causes mad crashes ... hence why i do window mode. But yet only do window mode if your PC can actually handle it ... to many kids play this game with bad processors
.