Have you tried using the "menu" key to completely back out and then hit play?

By using the menu button you can also back out and select other music.

To further elaborate: "Enter" drills down and "Menu" backs up. "Play" selects whatever is highlighted. So... if I'm queing things up I can select "Artist" by pressing "Enter", Select "AC/DC" by pressing "Play" or drill down into "AC/DC" (by pressing "Enter") to pick a certain Album or song. From there I can back up to the artist level by pressing the "menu" button and select all of another artist such as Stevie Ray Vaughan by highlighting that and pressing "Play" or drilling down by pressing "Enter". When I'm through with my selections I hit menu until I see the track info and hit "Play".