The user needs Publish rights to be able to add publish anything to the stream. If you want to allow him to be able to create new apps as well then he'll need Create rights too. In that case you'd likely also hand out Update rights. Perhaps the online help can give you more information.
Have you given a role to the user. If you just provide a token it will not be suffice. You need to give the appropriate rights as well. Try providing the user with a content admin role.
