HelpWindows7.com

[JIT]

I installed Call of Duty 4. It works fine with single player but with multiplayer punkbuster gives an error 'Unknown API function 131134'.
How to fix this issue?

[lambert]

I also cannot play online games with punkbuster on Windows 7.

[adelbert]

Have you tried to run the game with administrator rights (right click the game--> properties--> compatibility tab and then check run as admin)

[isaac]

I believe that Windows 7 causes the issue, as Punkbuster is not updated with Windows.

[kenneth]

To solve this issue first you have to find the PunkBuster Executable file and run that in Vista Compatibility Mode and see if that helps resolve the issue. If not then you will have to wait for PunkBuster to solve this issue.

[jerome]

Ok seems you can run PunkBuster on Windows 7 after all. I have found this works fine, but only on Windows 7 build 7000.
(1) Enable Vista compabitility for PnkBstrA/B.exe in c:\windows\syswow64 and c:\users\your_username\appdata\local\punkbuster.
(2) Run the above files with administrator rights.
(3) Enable Vista compabitility for C:\Program Files (x86)\Activision\Call of Duty
(4) – Modern Warfare\iw3mp.exe
(5)Run iw3mp.exe (Call of Duty 4 mp) without administrator rights