but the plug-in do not uploaded,or show anything else.

However,I've uploaded data importer plug-in to ow_plugins folder and unpacked,then installed from ADMIN AREA.
after that, inserted the salt to proper place.and tried to upload the backup zip file.
I got the error dateimport+not_valid_backup_file.

I've checked careully,that was a valid zip file,and I've tried with generating 2 different backups different time from wall.fm
IS THERE ANY OTHER WAY TO INSTALL BACKUP FILE,LIKE HOW I INSTALLED PLUG-IN?
IF NOT PLEASE MAKE A SOLUTION.