Can you post a dumper.*.debug and chunker.*.debug files?
Those file don't exist in /var/adm/amanda/ORBnet anywhere. There is an 'index' sub-directory in /var/adm/amanda/ORBnet with further sub-directories named for the 3 systems set up as clients in the 'disklist' file, but those sub-directories are all empty.
All the debug log info went into the one file by the look of it. Should there be additional log/debug info files?