External Firewire 400 drive not being recognized

Hello - I bought a Lacie 500 GB firewire drive to use for pro tools. I've
plugged it in & used it with my USB 2.0, drive is recognized & works fine.
When I try to use the Firewire 400, I am prompted to install drivers, which
don't exist ... LaCie tech support (terrible) insists it's a Vista problem
and that my drivers are corrupted. The drive shows up in Device manager as
'Lacie D2 external drive' but not under the firewire device, under 'unkown
devices.' When I right click there I get this error message:

This device is not configured correctly. (Code 1)

There is no driver selected for the device information set or element.

To reinstall the drivers for this device, click Reinstall Driver.

I'd love to reinstall the driver but Lacie insists there isn't one available
from them and if the firewire isn't plug-n-play, then it's either Vista's
fault or a hardware problem. (Firewire cable works fine, and the firewire
ports also work fine ... it is not a hardware issue unless it's the drive
itself.)

Anyone have any ideas? Thanks.