serial number problem

[joerock22]

I usually play pbem games on 1.06, but I've found an opponent who uses 1.07. So now I want to have two versions of ceaw on my machine, one 1.06, and one 1.07. The problem is that the game doesn't like that. Specifically, whenever I try to start the "second" version, I get a serial number error. What is the problem here? Does anyone have a solution? Thank you.