Battlefield: Bad Company 2 Vietnam - Cant join a server

Hey Guys

Im unable to join any battlefield Bad Company Vietnam servers at all, i just keep getting connection to server lost.

Im able to join normal BC2 servers, but not Vietnam servers.

I heard that is might have something to do with the vietnam expansion showing as registered but not actually being  registered at the same time causing it not to work.

So is there a way to fix it, or to maybe register it some how?

Thanks