I edited your posts to remove the code that was in them as it was difficult to navigate with all of the code present. I have added it to a file and attached it to the third posting that you made for the code.
When I check on the add to cart server behavior that is on the page it seems to be setup fine, but the form that you have on the page does not look like it is using the proper values.
In the add to cart server behavior you have it is looking for this posted value:
You do not have an add to cart form on the page with this value present, it looks like you might have removed this one. It looks like you have a second add to cart server behavior and form on the page, this one looks to be setup correctly, does it work for you?
In my previous statement about the add to cart not working with the id value I was incorrect in the way that I stated that. If you have a recordset on the page and have an add to cart and specify the recordset and id column it should be able to look up the item based on the id. Please post back with some info about the current state of the add to cart server behaviors that are on this page so I can determine how to proceed.