Cannot get WHMCS integration module to work!

I am trying and trying to get this module to work but I keep getting the error - Sorry this doesn't look like a WHMCS site at [http://www.northhosts.co.uk/] Make sure your WHMCS Integration settings are pointing to the correct URL and that the WHMCS site is set for the Portal template in Setup | General.

The urls are correct and I have had the theme set to portal to test - Im still getting this message.
Has anyone got any ideas?
Jon