Calculatons wrong etc

[binkent]

I am using Joomla 2.5.17 and virtuemart 2.0.26d and here is my site
http://www.supersignfactory.com/

When I Add more then 1 product to cart calculation is wrong, for example:  for 1 product
Name   SKU   Price:   Quantity / Update   Tax   Discount   Total
Air Dancer - Custom Lettered    11111   
$379.95
 
0   
$379.95
   
Product prices result       0   
$379.95
Shipping A-1
$49.95
No payment selected
Select payment         
Total:
$0.00
0
$429.90


when I add another to it
Name   SKU   Price:   Quantity / Update   Tax   Discount   Total
Air Dancer - Custom Lettered    11111   
$759.90
 
0   
$1,519.80

So it seems like it is taking 2 products and multiplying them twice how can I fix this?

also the modal add to cart window all of the sudden disappeared also.