@fourmat and @Cheloki
catalog\admin\includes\functions\db_backup.php
find line 34:
if (strlen($a_name) && $a_name !== '*') {
return '`' . str_replace('`', '``', $a_name) . '`';
Replace by:
if ( is_string($value) && (strlen($a_name)) && $a_name !== '*') {
return '`' . str_replace('`', '``', $a_name) . '`';