JoomSEF 3 as it states its for Joomla 1.5x?

Order Number: 18911

Have searched but didn't found anything.

Joomla 1.5.6
JoomSEF 3

At first onced enabled I got this error: Fatal error: Cannot redeclare class SEFConfig in /home/getback1/public_html/administrator/components/com_sh404sef/sh404sef.class.php on line 249

This went away when I disabled the sh404sef plugin (figured it wasn't needed as joomSEF is to do all the SEF related stuff now)

However all my links for categories and products show as DOMAIN.co.uk/products clicking on any category or product takes you to the same products page listing all the products?