I'm still using BE for Windows Servers 11d build 7170. I know it's old but it is still reliable. Our Sony SDX-570v tape drive bit the dust. I'm trying to find a tape drive that is compatible with the BE11d and the backup tapes we currently have our backup info on. Oh, yes. Our server bit the dust at the same time. I need to be able to restore the data from the tapes onto our new server. Not having much luck so far as the Sony SDX-570v drive is not readily available as a replacement.
I would even accept having someone attempt to recover our data onto an external drive it that would be possible.
Here is the Hardware Compatibility List (HCL) of Backup Exec 11d (7170).
http://www.symantec.com/docs/TECH46703 : Backup Exec 11d Hardware (HCL)
You can choose the tape drive which is supported by Backup Exec. Then you can check if the tapes where your data is present are supported by the tape drive. This way you will be able to access and restore the data from the tapes.
Personally, I would get a Sony SDX-570v tape drive from ebay or wherever, used is OK. I would also buy whatever LTO drive or robotic library that fits your needs and budget. I would then copy from AIT to LTO whatever tapes you are most concerned about. This is done in BE with a duplicate job. Then keep the AIT drive installed, but un-unsed, in case you discover antyhing else you need to restore in the future. Schedule all your new backup jobs to the LTO drive.