> The difference is that the good run was a level 0 and the run with the error
> was a level 1.
> What is the "Unexpected field value"?

Well that's the problem with cygwin... We have little reference.

Apparently running level 0 gtar creates a sort of index file, to use
in level 1 and compare files that have changed.

And it seems that in between the run 0 and 1 gtar cannot read the file
it created.

If you look at the sendzie debug you should see a command very close
to this one

gtar --create --file - --directory /local
--one-file-system --listed-incremental /local/Amanda/amanda-2.4
.5p1/var/amanda/gnutar-lists/coriolis_local_1.new --sparse
--ignore-failed-read --totals .

but that will say "gtar --create --file /dev/null ..."

Did that one completed without error?

Try to run the long gtar command by hand, with --file - and --file
/dev/null

Tryto extract the comamnd for level 0 and run it...

Check your version of gtar.

Bests,

Olivier