We have a weird problem. Everytime a customer goes to the checkout page, enters his address and click continue, the customer is redirected to the "Cart Empty" page. This happens for logged in user too - they get logged out. We have tried increasing cookie lifetime to 1 day instead of 1 hour, even a year, but with no success. Right now we have another onepage checkout module installed, and that works fine, but we would really like to get the original design working.
Any ideas to as what might be the cause?
