when i view source of the confirm page, the item name hidden form element is not being given a value:
<input type="hidden" name="amount_1" id="amount_1" value="20" />
<input type="hidden" name="item_name_1" id="item_name_1" value="" />
<input type="hidden" name="item_number_1" id="item_number_1" value="2027" />
<input type="hidden" name="quantity_1" id="quantity_1" value="1" />
the item name is not an optional value. make sure your add to cart buttons are setting the item name column of the cart properly.