The driver status of "tpconfog -l" is DISABLED

Use tpconfig -update -drive options with

-drstatus UP|DOWN|DISABLED

          Sets the initial status of the tape drive  to  the
          UP,  DOWN,  or  DISABLED  state.  Discovered drive
          paths are enabled (UP) by default. An  administra-
          tor or operator can disable or configure the drive
          path up/down.  The  user  can  also  perform  this
          action  with options in the Device Management win-
          dow.  A drive status of DISABLED  means  NetBackup
          stores  the path but never to use it. In addition,
          if  subsequent  discoveries  of  this  drive  path
          occur, NetBackup does not configure it for use.

Altho' it does beggar the question as to "why" they have been disabled in the first place?

An old T/N:

http://www.symantec.com/business/support/index?page=content&id=TECH68247