Plutonium

Mr. Android Shark#8420

So I've been using plutonium for the past couple of days and it's really amazing and I've not had any problems with the multiplayer aspect of it, but for zombies, the 3 expansions I don't personally own are unplayable which are the main ones I wanted to try the mods on. All of the maps that I don't own show a checkerboard pattern (it's not letting me upload an image) and then they just never load, I cant seem to find anyone else with this problem if someone could help id appreciate it a lot.