backup is done , but they are not in tar file format !!!!

[amanda]

Hello

I have just set up Disk Based Amanda backup , and every thing is fine,
I can do backup my files from remote computer,
but backed up files are not in tar format, here is my config, would
you please let me know why backed up files are not ending with tar
and tar can not open it.

files are created with following names in slot5:
00000-DailySet1-5  00001-hostname._tmp_backedup.1  00002-TAPEEND
00000.DailySet1-5  00001.hostname._tmp_backedup.1  00002.TAPEEND

more /etc/amanda/DailySet1/disklist
hostname /tmp/backedup mygnutar


define dumptype mygnutar {
   global
   comment "mygnutar dumptype"
   program "GNUTAR"
   compress none
   strategy standard
   priority high
}