Could this be a UAC problem on the VIsta side?

Can you turn off UAC and see if that fixes it?

Open up Control Panel, and type in “UAC” into the search box. You’ll see a link for “Turn User Account Control (UAC) on or off”:

On the next screen you should uncheck the box for “Use User Account Control (UAC)”, and then click on the OK button.

You’ll need to reboot your computer before the changes take effect.