For 'Simple invoices database backup' to work the first step is to make the tmp/database_backups directory(which is in the Simple Invoices directory) writeable by the webserver
To do this the in unix cd to the Simple Invoices directory (cd /var/www/html/simpleinvoices) and chown the tmp/database_backups directory to the apache(web server) user (chown apache:apache tmp/database_backups), in windows just browse to the tmp/database_backups folder and make sure its writeable by all users.
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