Thanks for the help, as it turns out the customer had a bad modem. apparently the error message read "Apple Remote Access, Modem not responding... error 6019" After trying both of the installed modems and getting the same msg. I recommended that he replace the modem. He was running an IMac with OS 9.2 and an internal modem. Other than that I don't know the rest of the specs.
Thanks Again for your time and effort.