Code Integrity Errors

I keep seeing these errors in my Event Viewer under Code Integrity. The only reason I was looking there, is because I had a BSOD the other day that involved the CI.dll. This is the error message I keep seeing in the Event Viewer:

Code Integrity is unable to verify the image integrity of the file \Device\HarddiskVolume2\Windows\System32\guard64.dll because the set of per-page image hashes could not be found on the system.

This message appears in the logs all the way back to the first day I installed Comodo.

Why is this happening? Is this something I should be concerned about?

I am running: Vista Ultimate 64, Comodo Firewall v3 and Nod32.