No carrier errors

I have a customer that is constantly reporting that she loses carrier while connected to a dedicated modem for stock quotes. This is a new computer and a new modem as well as software etc etc.
Her old system would never lose carrier yet this new system constantly drops the connection between the her computer and the other one. I tested the phone line and found no problems also called the software tech support and they saw no problems. Is it possible that there is some other feature in Win98that would be causing the program to drop carrier on a constant basis?