Thanks for the quick response. Just before you responded all of the products in my store started loading again and the checkouturl error was no longer occurring. I only enabled debug to see if the plugin was reporting any errors when it was unable to load products.
Later today I will try to add a new product to the store and see if I get any errors or if its related to another area of the site. I have installed the recent dev version and that is currently working.
Oli
