I have been seeing the same thing for about two weeks.

I'm running Fedora Core 5, and the same version of Amanda. Last night
my computer crashed, so I ran fsck on everything. There were numerous
errors on my / file system, where /var/lib/amanda resides. If those
were real errors I would think that fsck would have caught them.

I note in my yum.log:

Oct 07 08:58:06 Updated: tar.i386 2:1.15.1-15.FC5

I started seeing those error messages after October 7.

Possibly this is a bug in the latest FC5 tar? I'll check bugzilla
later today.

It's not a tar bug.

amanda-2.5.0p1 and previous are incompatible with the newer tar.
You should downgrade your tar or upgrade amanda to 2.5.1p1.

Things I have not yet tried: rolling back to the previous version of
tar; deleting the offending files.

Jean-Louis