RSS Graffiti does allow you to publish your tweets from Twitter to the Wall of your Fan Page, Profile, Group, or Event page. However you need to be sure you have followed the necessary steps setting up your feed before it will work. For example if you do not add your personal Twitter account then by default RSS Graffiti will use its own Twitter account to post. The issue with this is that Twitter only allows a certain number of tweets per account per day (it is in the thousands but we have over a million users) and once you meet that limit Twitter will simply stop posting. So to set it up properly follow the steps here.