How are you entering the serial numbers? Are you signed in as administrator or are doing this from a regurlar user account? Try to enter the serial number as an administrator.
One problem with the serial number may be, that you migrated an old "ProAppSystemID" file, that may be corrupted or write protected.
- Check, if you still have an old file "ProAppSystemID" in your System Library.
- Quit Aperture.
- Go to your MacintoshHD and open the folder "Library", then "Application Support", then "ProApps".
- Remove the File "ProAppsSystemID" to the Desktop, if it exist and restart Aperture.
- Reenter your serial number, hopefully for the last time.
All this has to be done with administrator privileges, because the ProAppSystem ID needs to be stored in the system library.
Sometimes Aperture writes this file to a temporary directory, when it cannot write to the Library. If the above does not work, look at the temporary directory /tmp
Use the Finder's "Go" menu
Go > Got to folder and enter /tmp into the textfield. If you see the file there, move it to its proper location
your MacintoshHD/Library/Application Support/ProApps/ProAppsSystemID
Regards
Léonie