Ultimate_SEO Contribution problem

[a1domain]

Hello Everyone

 

I installed "Ultimate_SEO_url" contribution

 

http://www.oscommerce.com/community/contributions,2823

 

 

on my website www.acorngiftsnetwork.com

 

but now when you click on any link on my FrontPage it will give error

 

Call to undefined function: read_cache() in file catalog/includes/classes/url_rewrite.php

 

can you plz guide me why this error occurs ?

 

Waiting for your reply.

 

Thanks in Advance