ISerialNumber realy can get ID serialnumber ?

Dear all:

When I use ISerialNumber to get serialnumber of InDesign, in CS3, the serialnumber string just have 20 chars (Serialnumber should have 24 chars);

And When i run in CS4, the return string is unknown numbers string,

Any body can tell me why ?

Thanks advance.

Best Regards,

Huwei