Instructions
Verify that the "Rock Band 2" servers are still online. As of January 2011, Harmonix still maintains "Rock Band 2" online, but a publisher can choose to turn off a server at any given time. Without online servers, there are no more updates. Check the Harmonix website (see Resoureces) for the current state of the servers.
Navigate to 192.168.1.1 in your Web browser. Type in your router's user name and password, set when you installed the Internet. Set your router settings to "Keep Alive," not "Connect on Demand." This ensures the router is always online. Consult your documentation for steps specific to your model of router.
Reset your PlayStation 3 to factory settings. There may a problem with your configuration. The option to restore to factory settings is under "System Settings."