Can you not tell Pest Patrol to ignore the Spywareblaster directory?
I might do an install of pest patrol later to see what I can find if no-one resolves this for you before I get home
edit:
Just found this and they supposedly fixed the problem with an update somewhere around the 10th of June
http://www.wilderssecurity.com/showthread.php?t=33822
Will have another look later if you still have no answer