Trying to get property of non-object

[eluser]Unknown[/eluser]
A PHP Error was encountered

Severity: Notice

Message: Trying to get property of non-object

Filename: models/redux_auth_model.php

Line Number: 505


This is the line 505:

502 // Group ID
503 $query = $this->db->select('id')->where('name', $this->config->item('default_group'))->get($groups_table);
504 $result = $query->row();
505 $group_id = $result->id;

I've attached the file in a zip.

Thanks!