my friends and I bought the first decade c and c pack. (has all the command and conquer games). the three of us use all hookup to a switch and play together in a network. we can play generals with no problem what so ever, the problem occurs when we try to play zero hour (generals expansion). when we play, the game always loads but after ~5-15 sec. , we always get a "mismatch synchronization error".so we experimented a little and the other two guys can play together with no problems, it only occurs when I try to join. I am using vista and the other 2 guys are using xp. are firewalls are down and we can try immediately after playing a round of generals. our operating system is the only difference that I can think of. Can anyone help?