Ok, just went through your shopping cart. The cart does not follow the normal virtuemart flow. In the normal flow,
- page a, select shipping address
- page b, select shipping option
- page c, select shipping method
- page d, confirm order
In your shopping cart you have combined all 4 of those steps into 1 page, which is why AwoCoupon does not work. I can look more at your cart, if you like, but please pm me credentials to access your webserver files. There is not much I can do without looking directly at the code.
Hope it makes sense.