iMessages not working after using MacPostFactor OS X 10.8

[WizOfRedstone]

I was succesful in installing OS X Mountain Lion (10.8) on my MacBook 3,1 but when i tried to sign to iMessages and FaceTime it got an error saying" unable to sign into iMessages at this time on this Mac" and then it provided me with a validation code. When I called Apple they said my Mac was already unblocked and they wanted me to buy OS X Lion (which Im not doing). Is there any other way to get it to work or no.

P.S I can sign in to the iTunes store.