Plesk 8.0 backup through shell

[diadem.support]

Hi,

I was trying to take psa backup through the command line using
the command usr/local/psa/bin/pleskbackup --all -verbose /backup/psadump-21-04-06 but surprisingly there was no backup at the location /backup/psadump-21-04-06 after its completion.From the process listing we found that the backup process was backing up the data at a location "var/lib/psa/dumps/tmp".But alas there was no content in this location also.Can somebody guide me the procedure.

thanks