Modem installation problems w Latitude C 600

I don't believe this to be in the FAQs. I downloaded the driver, but it will not install because 'NKTERN.VXD' either isn't there or can't do it. It's all gettin to be a vicious circle with the hardware install program. It detects the modem, but tells me there's a problem. When I click on 'update', it tells me the best choice is already there..., etc. Help!
thx
-FJS