I have just finished a conversation with Motorola Tech Support Level 3. The problem is a conflict between Google Play Music and the Dock Application in the Bedside mode. When you have a Music album selected in Google Play Music the Bedside Dock mode will crash. To fix the problem go to Setting/Applications/All and select Google Play Music. Reset the application by uninsalling updates or by clearing data to zero. This removes the albums you have selected from the play application. If albums are still shown in the google play application go to another page and come back this should cancel the albums. The play application should not show any albums selected. Dock function should now work in Bedside mode.
I'm not sure this is
entirely accurate, but you helped me launch the dock application successfully.
It's definitely a conflict with Google Play Music, but it
may not be having an album selected that's the problem. I just encountered the issue for the first time, and after reading your post, I realized that I had deleted some MP3's stored locally on my SD Card. Just as a test, I went into Google Play Music, and
selected an album and started playing a track, then paused. I then tried to launch the bedside dock and it worked.
BTW, I have the Atrix HD which is essentially AT&T's version of the RAZR.