Plutonium

nvm after further research, i need to download the DLC's, how do i do that without buying on steam?

When I reinstalled plutonium today after about 8 months of not having it, nothing is working like it used to. I was always able to play any zombies DLC I wanted to, but now when I select one it just turns to blue and yellow squares covering the screen. Anyone know the problem? Any suggestions?