If you've preordered and have beta access, obviously you've already paid and the coupon can do nothing. If you've preordered but waiting for Beta 3, you can always email sales@stardock.com to cancel your pre-order, and do it again with the coupon code. This only works if it hasn't been processed yet, though.
Like I said in another post, I preordered a few days ago and so have no beta access. Otherwise, I wouldn't be saying anything.
I know most here are Stardock fanboys and all, but this seems inherently unfair.
And yes, I could go through the process of canceling and reordering. But should I have to, if Stardock is such a great company?
Alan