I have the GalCiv2 Gold edition installed on my system. I just installed the 1.5X patch and had trouble activating it. It kept saying there was a problem with the serial number even though I had entered the code that came with the discs, and double checked it several times. Lo and behold, after getting my serial info from Stardock, it turns out that my Dark Avatar XP has a different serial number that I didn't even know about. This is really a dumb way of going about things and should be fixed.