USB/Serial Modem problem

I have a Imac 24" 2.33 GHz Intel Core 2 Duo with 2 GB memory with Mac OS 10.4.9

I am running Parallels Build 3188 with XP

I am a physician in Canada and have to submit my "billings" via a data/fax modem. I initially tried a USRobotics external USB modem but could not connect to the government site. I then Purchased a USRobotics serial modem (Model #64-005686-05) with a Belkin USB/Serial adapter. Everything seemed to install OK and when I connected to the Government site I was succesful!! Unfortunately after approx 2 minutes the VM crashed and XP restarted. This has happened repearedly.

Has anybody had this experience? Has anybody been able to get a modem to work

Thanks

 

Short answer for me is no. I have tried Bluetooth, serial and USB connections.