page check out error

[mgs5]

Hello,

 

My website link is meracart.com When an customer adds the product to cart and goes to check out, it will ask for either to register or use the credentials if already registered. When the user enters the logon credentials the payment gateway options would be shown (only for India shipping and accepted terms and conditions.) When the payment gateway is clicked it throwing an error invalid amount.

 

But the payment gateway works fine, if the customer registers or login initially and then add the products to the cart for the check out.

 

Please help.

 

 

Br,

vishnu.