Plutonium

Yep I have zombies downloaded, I can play it just fine without plutonium.
And yes, I'm launching it from the launcher. Also tried doing it through PL BO2 in-game menu, but same exact problem.

Multiplayer works just fine, but whenever I try to play Zombies it'll launch the game with the title screen frozen and then everything crashes a few seconds later, no error message or anything.

I have the same issue. The multiplayer launches with no problem, but zombies will launch the game and immediately crash, no error message or anything.