There is no path to the given drive or the path to the drive is offline or the source of the path to the drive is offline. The indicated volume may be still on the drive.
The drive is inaccessible.
Ensure that a path is defined to the drive. If there is a path defined to the drive, make sure that the path is online and that the source of the path is also online. Run the AUDIT LIBRARY command after the problem is corrected.