iw3mp.exe crashes when I try to start CoD 4 multiplayer.

[Hotline]

The title is pretty self explanatory, but, I can't start up Modern Warfare's multiplayer. Right when I choose the "Multiplayer" option, the screen goes black, and I'm greeted with an error message saying that. I'm using no mods, or hacks, but I never installed the latest version of PunkBuster.

[Danneh]

You may need punkbuster installed. It wont be used if you have it installed and you connect to a server that doesn't use punkbuster

[{ABK}AbbySciuto]

The version of PBSetup.exe you get with the Steam version of CoD4 is out-of-date. Download the new version from the PB website, replace the one in the steamapps\common\call of duty 4 with the new one, and run it. Add CoD4 and update the PB libraries and it should work.

[editline]2nd January 2011[/editline]

Also turn off the Steam Overlay for CoD4. Punkbuster hates it.