I have installed GC1.0.5, and then reverted to some older files from 1.0.4 as described above because I use flat rate shipping. My server does not have getallheaders() defined. I still get the error message about "headers['Authorization'] is NULL" using the newest responsehandler.php so I still need to comment out the two sections. I do not know what is causing this behavior.

Once I went live with google checkout, I got an email from Google that my account would be suspended if I did not put a button for the gift certificate items that shows that those items are not available for Google Checkout. I don't know if that means that if there is a gift certificate in a shopping cart, then I would also need the disabled button in the shopping cart as well. I ended up taking down gift certificates as they are rarely purchased anyway.

When viewing an empty shopping cart, I get the normal message that the shopping cart is empty, followed by Featured Products and whatever else normally follows, and at the bottom it says "-Or use-" followed by a button for Google checkout not available for this purchase.