This error message indicates that you have not signed up for Amazon Simple Email Service. Even if you currently have an AWS account - with an Access Key Id and a Secret Key - you still must explicitly sign up for Amazon SES.
Sign in with your Amazon user ID and password.
On the Usage Reports page, look for a drop-down list of services that you have subscribed to. Verify that Amazon SES is in that list.
If you don't see Amazon SES there, please go to http://aws.amazon.com/ses and click the button marked "Sign up for Amazon SES".