"When I'm in a game, it is very jittery, even though i have a 2.0 mbit cable connection. Also, a few seconds later it either disconnects me or crashes. Is this related to the operating system?"
I'm trying to play MTA:VC on 98se and am having the same problem. When i connect to a server the other players are either frozen or they teleport to other locations. A few seconds later i get disconnected and it says it's timed out. This happens on every server i try. My connection is 1.5mbit down/384k up so bandwidth isn't the problem.