Anything could be an issue. You are trying to restore data made with a product that is 13 years old. Since that ability is not tested or officially supported, you may be the first one in the world to attempt it. Since this is not intended for production use, you will probably be violating a number of compatibility lists, but desperate times call for desperate efforts.
What type of tape cartridge is it? Back in 2006 a lot of different tape formats were supported. DAT/4mm, DLT, SDLT, 8mm, SLR, LTO1, LTO2..
Do you have a working tape drive that can read that tape cartridge?
Do you have an appropriate HBA to connect the tape drive to a server?
Are you trying to restore simple files? That is possibly going to work.
If you are restoring databases or anything that required a BE agent, it gets much trickier and you must have someplace to restore these things to.
If you were to get your hands on BE 11d, would you have a server with an operating system that it runs on? I believe that BE 11d would not run on any modern operating system.