I solved my various "Insufficient O/S Privileges" and "No Packet Flow" errors while running Call Of Duty 1.5 using Wine on PunkBuster-enabled servers.

Download pbsetup.exe from here.

I had to change ownership of the CoD directory to my user (user in the below example):
Code:
sudo chown -R user:user /usr/local/games/cod
Run pbsetup.exe:
Code:
wine pbsetup.exe
select Call of Duty and point it to your CoD directory (e.g., /usr/local/games/cod). Run the update to install PunkBuster.

Run Wine config:
Code:
winecfg
Add application:
Code:
/usr/local/games/cod/CoDMP.exe
and select Windows 98 as the Windows Version.

Run CoD and it should work.