now I have different error, sorry to ask again:

cd /oraappl/pca/vprod/vprodarch
ls -lrt|head -`ls -lrt|awk 'END{print NR-1}'` > backuplist.log
gtar -cvf /oraappl/pca/backups/nightly_offsite/vprod_arch.'date +%m%d%y'.qz -L b
ackuplist.log
exit

vprod@findb > . ./arch_backup.ksh
gtar: backuplist.log: Invalid tape length
Try `gtar --help' or `gtar --usage' for more information.