Instead of manually downloading and installing, I use the add/remove feature of ubuntu. Start the Add/Remove app by clicking Applications > Add/Remove... Then click Preferences and on the Ubuntu Software tab ensure that the following are checked:
- Community-maintained Open Source software
- Software restricted by copyright or legal issues
- Source code
Click Close. Now it will ask you to reload, click Reload. Now search for banshee and Ubuntu restricted extras. Install them and everything should work for you.