Login Radius Fatal Error

I am only using BBPress not WordPress. I wanted to add functionality to allow visitors to use OpenID and going through the forum I came accross using Login Radius.

I uploaded it to my-plugin and I see it in my plugin section.

When I click activate though it gives me a Fatal Error

Fatal error: Call to undefined function get_option() in /public_html/forum/my-plugins/loginradius-for-wordpress/LoginRadius_function.php on line 137

Any help would be appreciated.