I'm new and having problems.
I had an existing Google account, I did not have it set up to use Checkout.
I got my Atrix and started getting some Apps from the Market. I decided to get one that wasn't free. I tried to buy it, and it said none of the accounts on your phone are supported by Google Checkout.
I went back to Google and set up the Checkout.
I've resync'd the phone to the account on Google, but it still says the same thing. I've even deleted the cache and signed into the Google account again on the Atrix. Still getting the same message that none of the accounts on the phone are supported by Google Checkout.