Hi Keith,
I'm affraid it's a database version problem. Your 2012 backups have database vesion=12 and your current catalog uses version 14. If this is the problem, I'm not sure it is, then you can solve it creating an 5.0.3 director virtual machine with an empty database and restore the 8 volumes and jobs with bscan.
For old backups, I normally use bextract for restores, mainly because I don't have file retention times too long and with bextract I can easly do full restores or select folders/files I want be restored (and you can use only one volume or all of them).
Best regards,
Ana