DEC UNIX and "dump" problems

A previous SysAdmin made a "dump" script for backups on out Digital UNIX
machine.

I'm very new to Digital UNIX (Well, UNIX in general) and I can't quite
figure out what I am doing wrong.

The script, is simple:

dump -0uf /dev/nrmt0h /
dump -0uf /dev/nrmt0h /usr
dump -0uf /dev/rmt0h  /var

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Now, I get an error when running this script as follows:

webserv> dump.com
dump: Dumping from host [hostname deleted]
dump: Date of this level 0 dump: Wed Jun 11 16:56:42 1997 EDT
dump: Date of last level 0 dump: the start of the epoch
dump: Dumping /dev/rrz0a (/) to /dev/nrmt0h
dump: Mapping (Pass I) [regular files]
dump: Mapping (Pass II) [directories]
dump: Cannot open device file /dev/nrmt0h
dump: NEEDS ATTENTION: Do you want to retry the open?: ("yes" or "no")

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Everything is connected, apparently working as it should.  Now, when doing
a "file /dev/rmt0h", here is what I get:

webserv> file /dev/rmt0h
/dev/rmt0h:     character special (9/6146) SCSI #0 TZ86 tape #2 (SCSI ID #6) (SC
SI LUN #0) offline

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The "offline" is what gets me.  I'm sure there is a simple solution to this.  But, I really need some help.  I have not done a backup in almost a month, and I'm getting worried!  Thanks...