I just got the Space unlimited Collection, here in the UK. It has Sins, Gal Civ II - Ultimate, Star Assault and Dark Star One
I bought the game from a retail store and it was sealed, and yet there is only 2 serial number stickers on the inside of the case (with the words "serial number" in German as " Seriennummer"). Neither are recognised in the registration page (they do not show what game the serial number is for!) and when entered in the Serial Update option in game, just leaves the game frozen after a while of accessing the net.
I too am going to have to contact support, so it's a Space Unlimited compilation problem with Stardock allowing various compilations with the necessary "administration" of it, regarding their Serial Number systems!