Multiprey help

Ok, so I have the Collectors editon, and I am fully upgraded to 1.4. Whenever I try to join a game, it tells me I don't have some required files, and the required files are not provided in the server. I can create games but not join them. Can anyone help? I know there isn't much activity on the PC boards, but I might be able to go LAN with my roommates if I can figure this out.