We've removed software and reinstalled and also removed the AntiVirusProduct line from wbemtest Query Results screen but problem persists. We did find the issue stayed away for about a week. I think a reboot (or two) may cause the problem to come back - I know for a fact it was working for me on Thursday/Friday last week at one of my clients but failed this morning (the following Monday).
Have not tried removing the files and registry as per Aravind's response yet - I'm going to try that now.
Both machines I've had this on have been a SAV to SEP migration. Both clients running 11.05
I have a ticket open with support but so far they only suggested the wbem fix.
Unfortunately this is holding me up from rolling out 11.0.5 as I can't afford 100+ desktops to have this issue.