I tried to install your contribution. Wanted to test it si installed on clean osC shop overwrting old shopping_cart.php
Everything was ok but when I pressed `google checkout` button I got this error.
Error parsing XML; message from parser is: Invalid value for body of merchant-calculations-url in checkout-shopping-cart/checkout-flow-support/merchant-checkout-flow-support/merchant-calculations: URL contains illegal characters
Can you advise what can it be and where should I look to fix this.