when i try to upload a face to the store i get an error

That means the manifest ID you are using is already in use.  Did you start with an app from github by any chance?  That WF is probably already using that manifest ID.

Go into the manifest editor in eclipse, and you'll see this:

Hit "generate" to get a new ID, and save the manifest.  Rebuild the .iq, and you should be able to upload just fine.  This is a one time thiong.  You want to stay with the same manifest ID for your app.

thanks