There is currently a known issue with authorising the V-Station 1.5 in MOTU Digital Performer which causes a message to appear saying that the serial number is invalid. To get round this problem you can use a different AU host to authorise V-Station. AU Lab is one application which can be used for this and it is free with OSX TIger. If you do not have AU Lab installed on your system then you can get it from the OSX Tiger disc. From the disc, run the package:
Once installed you can find AU Lab in:
If you do not have the OSX Tiger disc then you can download Xcode free from here (you will need to register with Apple first).