Animation and Rigging Tools: FAQ, Known Issues and Feature Roadmap

Check to see if you have a userSetup python file in more than one spot. Sometimes, people might have one in maya/scripts, and also in maya/versionXXXX/scripts and these will conflict.
Also, in your maya/versionXXXX/scripts folder, check to see if you have a mayaTools.txt file. If you do, open it and make sure the path there is correct, or delete it and it will prompt you once again on opening Maya to locate the tools directory.

EDIT: Btw, sorry for the late reply. Been focusing on one of our game projects and accidentally letting my inbox and forum threads go unattended.