I don't have a 900, so I can't say for sure what the problem is without more info. First, what version of Python is on the 900? Open an xterm window and type python. The first line will say what version is used. Type 'quit()' or Ctl+D to exit Python.

From the xterm window, type:
python /usr/lib/mlbviewer_gui/mlbviewer_gui.py

If it is up and running and you see the games listed, that's a good start. Open the configuration panel. Is 'Use Mob' checked? It is required. Confirm your username and password are correct. Click on the Player Config tab. Does the 'audio' entry say 'mplayer'? Save your config if you made any changes.

Click on a game in progress. Select either the home or away feed. If it does not start (it does take some time to connect and build a cache), look in the xterm window. Are there errors? If so, copy and paste them here. (There are informational messages that are not errors, like 'show available' and 'refresh_listings')

You should only need to package with 2010 in the package name.