Hi...
Im still having data mismatch problem... I've reinstalled the game and I downloaded newest OEM pack. I don't know what should I do :0 I really want to play multiplayer but I can't :( :(
Make sure you're' downloading the full OEM pack and not just the patch, the full pack is nearly 2GB in size. If that's not it then you might have more than one copy of the OEM bikes in either your docs folder or the game install directory and one is an old version.