[USR-TC] Problems w/ a Total Control

Hello everyone. I have a US Robotics Total Control Enterprise Network Hub that is having some issues. People dialing in tend to get weird errors, like 619 and ppp errors. Also, they get disconnected after being connected for a short period of time. The only thing that helps is rebooting, but you have to do that several times for it to pick up calls. Any help yall could give would be appreciated. Thanks in advance. Chris Hamersly