the TARGET //192.168.0.164/username/mailbackup
If 'mailbackup' is the defined share then the target woulld be //192.168.0.164/mailbackup.
The syntax is //server/share not //server/share/blah.
# smbclient -L //< computer name >/ -I < ip address >
Displays a list of shares on the machine. Just hit enter when prompted for a password.
Darrell