Your game version does not match the host's version

[Deadliestmuffin]

This has been an error for ages. When we were having LAN-parties, there were always someone that couldnt connect to the server. This error message showed up:

"Your game version does not match the host's version"

This is strange, because i put the game on a memory stick, and passed it around the room. Everyone was running win 7, and everything seemed smooth until that one guy coulnt join. When you go back to the main menu, it even tells you that the version is different, even when i just gave him my memory stick 2 seconds ago.

I have tried reinstalling, redownloading, repatching, and none of it works.

The first one says:

v.2.00.5366

The second one says:

v.2.00.4059

PLZ HALP QUICKLY