In Vista, despite you being an Admin, apps are run as normal users for security reasons. Which is what UAC is, User Account Control.
If you don't remember switching it off, download the skin plsk, right click and click "Run as Administrator"
It might as you for an admin pass (from a non admin account) after its asked permission to seek elevation else it just asks you to admin authorise it and you're done
This is what matty was referring too.
Update: Can't run plsk as admin
I have another solution. Am typing it out now =p
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