I almost have it, I can do amcheck -c, but amcheck -t will
return
  ERROR: file:/home/software/amanda/backup: not an amanda tape
       (expecting a new tape)

$amverify Daily

    No tape changer...
    Tape device is file:/home/software/amanda/backup...
    Verify summary to amanda
    Defects file is /tmp/amanda/amverify.30434/defects
    amverify Daily
    lun dic 30 12:50:39 CET 2002
    Using device file:/home/software/amanda/backup
    Waiting for device to go ready...
    Rewinding...
    Processing label...
    ** Error reading label on tape


When I try to do amdump

   *** A TAPE ERROR OCCURRED: [not an amanda tape].
   Some dumps may have been left in the holding disk.
   Run amflush to flush them to tape.
   The next tape Amanda expects to use is: a new tape.

   FAILURE AND STRANGE DUMP SUMMARY:
     agisrv03.a /etc lev 0 FAILED [can't switch to incremental dump]

That's my tape config.
   tapedev "file:/home/software/amanda/backup"
   tapetype DLT

I mkdir /home/software/amanda/backup/data from the amanda user.
And I made sure amanda could write there.

Any hints ? Thank you for your time.