Hi Rich GU,
Please can you make sure you are using the very latest version of Parallels version 3 build 5582, as the release notes for this version specifically mention improved support for National Instruments USB devices.
If however you are already running build 5582, please contact parallels directly as the issue lies in their USB emulation (virtual) layer, and that is something we do not have access to.
The way to make sure this hardware defiantly works with your Mac is to open the Mac in Bootcamp and try and install the hardware.
Regards
JamesC
NIUK and Ireland