Cannot add items to cart

[futuretek]

Hi All,
Trying to solve a problem that has cropped up. I can add an item to the cart from the category Buy Now button. However I cannot add an item to my cart when I am in the items description. The item is just not added. From what I remember it had always worked...at least I think I initially tested it.

this is the form code

<form name="cart_quantity" action="http://www.site.com/catalog/product_info.php?products_id=489&action=add_product" method="post"><table border="0" width="100%" cellspacing="0" cellpadding="0">
<input type="hidden" name="products_id" value="489"><input type="image" src="includes/languages/english/images/buttons/button_in_cart.gif" border="0" alt="Add to Cart" title=" Add to Cart "></form>

I have checked the code against the original and I see nothing out of place.

Any ideas?

[futuretek]

Been going through it over and over again I can't see whats wrong