Google Checkout Error - Invalid or not supported Message

Hey all... I have been trying to get the google checkout Mod installed for a while now, but for some reason I am not getting the orders to show in my Admin section. When I check google, everything is correct... The order processes, i get the email, etc - but I do not get anything in my Zen Admin.

I can't find out how to fix this... The error showing in the google logs is as follows.

https://www.MYSITE.com/googlecheckout/responsehandler.php -- the error we got is: Send failed with code: 400. Response body was: Invalid or not supported Message

Any help is much appreciated.

Thanks

Also, what callback method should we be using with Google Checkout, XML or HTML (name/value pairs)?

Never mind, I think we've got this figured out. For those who may be getting the same error we switched our callback method to XML and it started working.

Thanks for the Mod.

I am having the same problem. Can you tell me exactly how/where you fixed this. I am getting the correct response from responsehandler, etc. but can't get anything to show up in my Admin section. Please help, this has been VERY frustrating, and I can't get a direct answer from anyone.