I have the serial numbers now and installed my airports but when I bring up the addon manager I can't paste (what is is not being able to cut and past about?!?!?!?!)
Of course it is able to paste: if the standard hotkey doesn't work, right-click on the blank space where you are supposed to type the key and select Paste from the menu.
and I can't type in the serial number either as it is greyed out.
Now I'm failing to understand what you mean: what's "greyed out" ? The dialog where you are supposed to type ( or paste ) the activation key never greys out. The only thing that eventually CAN be greyed out is the "Register Serial" button, but that means that product is ALREADY Active ( and the Addon Manager will tell you that ), but if the Register Serial is greyed out, you are not even supposed to see the registration dialog when you type the key because...you don't need it, the product is already active.