742a7de1-9a58-42ef-8f8e-a05d35df1f0f access api bad cart click correct encoding error error-message google-checkout message password serial-number shopping username utf-8 version working xml xmlns

I'm getting an error message when I click the "Google checkout" from my shopping cart....it's the following message (what is it and what do I do to correct it???)

<?xml version="1.0" encoding="UTF-8" ?>
- <error xmlns="http://checkout.google.com/schema/2" serial-number="742a7de1-9a58-42ef-8f8e-a05d35df1f0f">
<error-message>Bad username and/or password for API Access.</error-message>
</error>

IT'S WORKING NOW !!! - thanks!