Well, I did this to make it work, I don´t know if you can skip steps.
Enter to c:\windows\system32
put compatibility mode to vista to pnkbuster or something like that.. A/B
Restart services in services.msc
Download pbsetup, a file from evenbalance.com (support section, ow to update punkbuster manually).
add your game and update it (remember to run it with admin privilegies)
If you can't play (you click but it doesnt load a map) it is because you can't log in with your profile. You need to use this program: NickKusters.com - Request Download - Nick Kusters Custom Software Solutions (NKCSS)
Called: NKCSS CoD 5 WaW Profile Fix
You can get it from TPB also
Run it with admin privilegies, and follow instructions.
You will now play!
I can't test the MP because I got a "trial" copy, but I don't get any "PunkBuster is disabled" nag screens.
Test and report!!