order total missing error PayPal

I get this message when I am trying to check out.

There was a problem connecting to PayPal to setup your purchase. Please try again.
10400 - Transaction refused because of an invalid argument. See additional error messages for details. - Order total is missing.

I was able to start the check out process, I entered contact information, but saw above mentioned error when proceeded to next step.
WHat is the issue?

my store is here:
http://ns.pulsohispano.com