ERROR: The form cannot be rendered. This may be due to a misconfiguration of the Microsoft SharePoint Server State Service. For more information, contact your server administrator

You need to make sure that the state service is started and associated with your web application that will be used to publish your workflow into it. Check the configuration through Central administration--> service application association.

Solution: http://social.msdn.microsoft.com/Forums/en/sharepointworkflow/thread/521db715-0d76-49ce-be36-7c37cfb8026f