It may have been installed in the admin account, which means that the serial number information is not accessible by the student.

To fix it- log on as admin. Follow the steps below:

If you copy the preferences file for the local Admin user, and place a copy of that file in the same location as the Curve4 program (in the Curve4 Program Files folder), then that file will used for serialization purposes, while still saving a regular preference file in the normal place for each user.  This allows users to have their own prefs, eliminating the need to enter username/serial number info for each user.

The preferences file should be here:
C:\Users\{your home user}\AppData\Roaming\CHROMiX \Curve 4 Prefs