Evenbalance had a problem with their implementation on the fairer platform a few days ago.  Solution from Aspyr's support team: 
  
  
  
  
We were given the following to try directly from the folks at PunkBuster. It worked for us. 
 
Download the following file: 
 
 
http://web1.evenbalance.com/downloads/cod4/mc002301.mac
 
After the file is downloaded place it into the install path 
>pb/dll folder. 
 
Let us know if this fixes things for you.