One of the SharePoint 2010 cool feature is Ratings, When you enable Rating setting from List Setting system prompt following error, this article explain how to resolve it.
No User Profile Application available to service the request. Contact your farm administrator.No User Profile Application available to service the request. Contact your farm administrator.
Go to Central Administration > Services on Server > Ensure that User Profile Service is Started ?
Go to Central Administration > Manage Service Applications and Select User Profile Service and Go to Application ribbon and click the Administrators button.
When you click Administrators button you will see below windows Select username and assign Full control under Permissions, now you go and enable Rating Setting you will not get above error.