One or more required files of the promods map...

[Tweezy20]

Today I have downloaded ProMods to play with my friends online .
It works alright in SinglePlayer mode as far as I can tell but whenever I try to join multiplayer an error pops up telling me this : " One or more required files of the promods map modification could not be found. Do you need help installing it?" or something along those lines .
I have all the DLC'S required to run the mod , the mod is up to date ( 255 on ETS 1.40) and I have generated the def file correctly.