This is certainly a legitimate question
From your initial post
""[90:54] Cannot open device (/dev/rtape/tape2_BESTn)"
The '/dev/rtape/tape2_BESTn' is a HPUX device file, so the media agent in running on HPUX
You did not include the entire error, but, as part of the error message, you can see
From BMA@[hostname]
The [hostname] is that of your Media agent
You will need to get with your HPUX system administrator, rebooting normally requires 'root' permission