Shopping cart broken ... ;(

Marketpress shopping cart was working like a charm. Something happened yesterday where shopping cart would not go pass Enter Shipping address ... it would just come back to Enter Shipping address no matter how many time user tried it. Also, shopping cart was not able to update or remove QTYs with Update Cart button.

So, we updated today to 2.7 of Marketpress and to latest WP version, and still same thing happens.

You can see it here here https://safetybright.com just add any product , go to shopping cart, and try changing QTYs or checking out past Shipping Address.

This is a HUGE deal for our client because their customers are calling and complaining they cant order...

You help GREATLY appreciated, as always.