I encountered similar issue here. Make sure you check the repository version against the client version, it should match. Sorry I cannot the latest KB McAfee released in Dec 12. It stated that if you used an older policy from a legacy ePO. You will run into a greatest risk of the policy not working. Hence, I had to rewrite the policy from scratch. Besides that issue, did you check the client services is running under the Task Manager? The cores services are mfefire.exe, firesvc.exe, and mfevtps.exe should be running to confirm HIPS installed properly. I hope I was able to direct you in the right direction.