Does your limited account have the rights to even run it? Might want to check which rights/permissions your account does have. Can you get it to work if you temporarily give your limited account admin rights? If not, then maybe you need to reinstall it while logged in to the limited account with admin rights, then just remove the rights when you're done installing. I use Avast on a limited account with only 'Poweruser' rights, and it works fine. Not sure though how it would work if I only used 'User' rights.