When a user clicks on a product to add it to the cart the "Loading graphic" shows up and just spins and spins and the page doesn't advance.

If you click the view cart link the product has been added to the cart.

The error message in the left hand corner of IE comes up with this

Unexpected ajax respone was received from the server
This may be caused by one of the following reasons:
- Server Transfer
- Custom http handler
- 'Incorrect loading of an “Ajaxified” user control'

It says to verify that you don't get an error set the EnableAJAX property to false

Code:0

In the store preferences I unchecked enable Ajax.

What else do I need to turn off or other suggestions on how to fix

Thanks