Do you have disk 2 in the drive? Using the first CD will cause a disk identification error. At least in the North American and UK English versions, the mentioned CD key is just a poorly worded error that it could not find the play CD in a drive (if it finds the first CD in a drive, it will not keep looking for the second, so remove the install disk). The Australian version does use a cd key.
Copy protection systems can have problems with particular optical drives, so trying a different drive (if available) may indeed help.
