You can delete outlook cache (extend.dat) to get rid of add-ins that are no longer available.
You can also check below KB article from McAfee. Hope this helps
You had posted in Community Help which is for problems with these forums.
I moved this to Business > VirusScan Enterprise for better attention.
Message was edited by: Ex_Brit on 21/05/13 9:01:56 EDT AM
Have you check the other option in the KB article?
If it still doen't resolve your issue, there is someone who can assist you further as this has been already moved to proper discussion group