Invalid token accessing checkout

Anytime I try to access the cart when there are no items in it (e.g., "empty cart") i get an invalid token. This happens whether a user is logged in and registered or not. Is there a way to fix this or trap the error to gracefully exit back to some page that keeps the session with the website usable?

this is in development, but I want to move this to prod as soon as possible.

www.development.mhill-images.com

It seems that you set the URL www.development.mhill-images.com/index.p...=items&task=edit&cid []=294 in the option "URL to redirect when the cart is empty" in the Checkout tab of the config of HikaShop.
That error comes from flexicontent which is displayed on that page.

If you set another URL in that option, you won't have the problem.