yoyu should be able to imnport the v7 catalogs into one of the newer versions
Just
Shut down Backup Exec on both old and new systems
Copy the *.u01 files to the new \Catlaogs folder
Restart BackupExec
See http://seer.support.veritas.com/docs/272886.htm to force a re-index of the catalogs
As I recall , there was a format change between v6 and v7, and I think you'll have to inventory and catalog those tapes individually