McAfee and RootKit

A recent virus scan hung up while scanning "rootkit".  I searched for a file called "rootkit" on my system and found none.  I ran the scan again and it completed OK with no viruses detected, but I noticed that scanning "rootkit" was displayed a number of times during the scan.  Following the advice in the forum I downloaded and ran Microsoft Safety Scanner which said no infected files were found.  I also downloaded and ran McAfee's rootkitremover which again said no Trojan viruses were found.  I've also run Safety Scanner on the other computer that I have on my home network and again it was clean.

My virus scanner version is 16.8.  Do I have a problem?