When registering with a different version's registration number in ArcGIS Desktop 9.3, an "invalid registration number" message displays.
If an authorization file (.esu9) from a different version is used, a message like the following displays:
This error may come up if an authorization file (.esu9) from a previous version of the software has been used. Authorization codes or files from different ArcGIS Desktop product versions cannot be used; for example, ArcView 9.2 codes cannot be used to register ArcView 9.3.
Request an ESRI Authorization file for the version of ArcGIS Desktop installed at http://service.esri.com.
The single use registration or UNK number must already be acquired.
To request a single use registration or UNK number, contact ESRI Customer Service at 888-377-4575.