A3M - Account Authentication & Authorization Module

[eluser]David Hyland[/eluser]
hi there. i'm probably making a school boy error as everyone else here seems to get it working but i'm getting the following error when signing up

Undefined property: Sign_up::$db
Filename: core/Model.php
Line Number: 50

Fatal error: Call to a member function get_where() on a non-object in C:\xampplite\htdocs\taskme\content\a3m_peanutbutter\application\modules\account\models\account_model.php on line 28

and on clicking through to google the following:

Fatal error: Call to a member function get_where() on a non-object in C:\xampplite\htdocs\taskme\content\a3m_peanutbutter\application\modules\account\models\account_openid_model.php on line 28

any ideas?