Mac OS X 10.6 Snow Leopard USB Drivers

I've tried repeatedly to install this driver but keep getting the msg

"System extension cannot be used.
The system extension"/System/Library/Extensions/CDSDAudioCaptueSupport.kext" was installed improperly and cannot be used...."

The installer that goes on to say that installation was successful. The file is there, showing a modified date of 12/17/08 and a size of 172 KB. Permissions are "Custom Access" with system R&W, wheel Read only and everyone Read only. My new Duemilanove appears to be functioning correctly (at least complies, uploads and correctly runs the "Blink" test sketch).

What's the significance of the apparent error? (Sounds as though it might only affect audio somehow?)

Any way to get it right?

Thanks!