First have your buddy go to evenbalance and get the pbsetup tool; this will update pb for all games so he doesn't have to do it online, which can cause lag: PunkBuster Online Countermeasures
Run the setup tool, then have him head to C\Windows\SysWOW64 and look for PnkBstrA and PnkBstrB. Right click on each file, select properties, then select the compatibility tab and check mark "run this program as administrator". Click Apply.
Then head to the game(s) folders for all the games that use Punkbuster. In the pb folder some games might also have PnkBstrB. Do the same thing and allow that file to run as administrator.