Black Ops 2 Error

I just bought a Black ops 2 CD key from Fry's and put it on Steam. I installed the campaign to my HDD, then my multiplayer and zombies to SSD. When I boot up campaign, all goes well, but when I boot up multiplayer, it gives me an error along the lines of audio file error cmn_root.all. Can someone help me with this? Do I need to install the campaign to my SDD?

Sys Specs

i5-3570k @ Stock Clocks
8gb 1600mhz Corsair XMS3
Win8 (64-bit)
128gb SDD
180gb HDD
P8Z77-V LX Asus
Hyper 212 plus cooling
GTX 650 ti with latest drivers
Corsair HX650