What is /db_backup ?
Is this the folder that you want to backup, or is this a text file in / that contains a list of files/folders to be backed up?
-f option needs a file name that contains a list of files/folders to be backed up.
If you want to backup the folder called /db_backup, then do not specify -f.
You also need to specify a schedule that is a User type schedule.
If Weekly_Full is a type 'Full' schedule, you cannot specify it in a user backup started on the client.
Hope this helps.
*** Edit ***
The error is actually telling you what is wrong:
bperror -S 241
the specified schedule is the wrong type for this request
Create a User type schedule with an open window during which users are allowed to start user-directed backups.
(Explained in Admin Guide I under 'Standard backup types' in Schedule Attributes tab section )
