The WebSphere Plugin comes with a plugin-key.kdb file upon installation, and contains a personal certificate that is set to expire by April 26, 2012. The keyfile itself also has a password "WebAS" that is set to expire by April 26, 2012. Action may be required to maintain encryption between the plugin and application server(s). This affects WebSphere Application Server V6.1, 7.0 and 8.0.
Refer to the Flash technotes from the WebSphere Application Server support team to determine if you are affected and what steps may be needed to correct this situation (direct links):