Newly installed Wordpress/marketpress: "Whoops, looks like you skipped a step!"

Hello,

I just installed WordPress and MarketPress to test out the store functions and I can't get past the order confirmation page. I get the error message:

"Whoops, looks like you skipped a step! Please go back and try again."

I am using Paypal express. The message appears after I login to paypal; then verify information; and enter my site's order confirmation page. Everything appears to be filled out properly.

This is newly installed WordPress site.
MarketPress in the only active plugin except WPMU DEV.
I've tried this on multipule machines (same error).
I've tried iexplorer and firefox
I am using the default theme "Twenty Eleven".
I've used both live and sandbox paypal accounts

All with the same error.

My site is http://www.white-elephants.com/
Please try it out and let me know your thoughts.

Thank you