I entered a ticket yesterday 20May2011. I'll post here too on the chance others may have similar issues.
I bought GalCiv2 Ultimate Ed (GC2UE) from Amazon. Installed OK.
Then I downloaded and installed Impulse. The MyGames tab shows GC2UE, update available, v1.97 (v2.03 available).
I created the registration entry, but got a registration for GC2EU (endless universe), not GC2UE.
I tried all 5 GC2 game choices - all registered as GC2EU. Apparently my reg key is specific to that variation of the game?
Impulse showed 2 entries - GC2UE (Stardock, status Update Available) and GC2EU (Kalypso, status Uninstalled).Both showed my reg key in View Registration.
I tried Installing GC2EU (a looong download, no request to insert the DVD).
GC2EU status is now Recently Installed, v2.03. Verify Install is "Installed Correctly".
GC2UE still shows Update Available, but update fails with message "your registration for this product is not valid". Verify Install is "Not Installed Correctly - Look For Update".
I also downloaded and ran the fix_registration.reg file with no effect.
My best guess is that my UE mistakenly got stickered with a EU serial code. Whatever the cause, it's hard to believe that registration issues haven't been fixed at this stage of the product's lifecycle...