Universal Login for Multisite

Is there a plugin or small code modification that will allow my users to login directly to their respective dashboard without reaching this error message:

“You attempted to access the (main site) dashboard, but you do not currently have privileges on this site. If you believe you should be able to access the (main site( dashboard, please contact your network administrator. If you reached this screen by accident and meant to visit one of your own sites, here are some shortcuts to help you find your way.” ?

All help would be appreciated! 🙂