Unfortunately, due to a strange, MS made, anomaly in Vista, you are not the "Global" administrator.
Your rights to several functions are curtailed.
It is not difficult to obtain the rights, but first, re-enable the UAC and try again to run the reg file. Acknowledge the popups from the UAC.
If that fails, try this.
Type Control Userpasswords2, in the run bar.
Click "Advanced" and then "Advanced" again
Clck users and then Administrator.
Untick "Account is disabled"
Now OK the windows, back to the desktop.
Log off. You will now see another logon entry for the Administrator. Log on with that and Try the reg procedure again.
If you are succesful, other advice is that you should then disable the Admin account again, as it leaves your computer more open to internet attacks.