Is there something obvious I'm missing, here? The same USB modem that works perfectly well in Bootcamp Windows 7 will not negotiate a connection when using a Windows 7 VM in Parallels. There has to be something obvious that I am missing. iMac 11,3 OSX Snow Leopard and Windows 7 Ultimate 64 Bit in the VM.
Hmmm.... For the moment, the problems seems to have been mostly resolved by reverting to the old modem driver from 2008 and starting my iMac with the 32-bit kernel enabled. I have no idea why this would have helped, since the 2010 driver worked perfectly well in Bootcamp. There's no reason for me to stay in the 64-bit kernel, so I'll give this a try for a while, and there's no way to tell if it's the 32-bit kernel or the old modem driver that has done the most good.