WP e-Commerce not re-directing when checkout is incomplete

If anything is left incomplete on the checkout page, the ‘This is somewhat embarrassing, isn’t it?’ page appears. If you hit the browser back button, you can return to the checkout page, but no errors indicate why the order didn’t go through.

I think it should re-direct the buyer back to the checkout page with an error indicating which field is incomplete. What would cause this? And what can I check for?

Thanks!