Because of vista requiring signed drivers, you must either turn off the check for signed drivers or install via device manager and point to your driver location.
On the little disk there should be a video of what is required to install under both vista and 7, worth checking out if this isn't resolved yet.
Depending on your patch level, you may not be able to use this following command, but it is worth a shot. You must run this as an administrator in a cmd window. Start>run
type "bcdedit /set loadoptions DDISABLE_INTEGRITY_CHECKS"