404 error when I look up MarketPress orders

For the last few weeks, every time I try to look up a customer order I get a 404 error. I can see the orders just fine in my dashboard, but when they lose their download links or tell me they never received their order emails, I like to send them the link to their order. I used to go to http://www.shinyhappyworld.com/store/order-status and enter their order number, then send them that link - but now when I do that I get a 404 error. I have to use this feature a lot and I have no idea what made it stop working.

Thanks,
Wendi