Pax Romana doesn't work....

Damn it!
I've installed this game(original version) and when I starting to play it ask me for the serial code. Well, i tried to find on the disk, inside the disk, in the manual, everywhere. But there is no serial code. what shall I do? Pleese someone help me...I spent something like 10€euro(ok it's not a big cost but....)for an original game that doesn't work...bye

Maybe it's the code on the back of the CD? (CD Key, like 111-AAAAA -- that's a made up one, BTW)

The activation code is on a loose slip of paper found in the original box.

I've tried playing the game...it could have been so great if not for the constant bugs (even after the patches). I plan on trying to play it.