Navigation from a BSP class method to a page.

How can i navigate from a BSP application class method to a page in the same application.

I need to display an error page (within the application) when an application class method returns false value, instead of going in every page and checking for the false value. I am directly trying to navigate from the method itself to the error page (if it is about to return false value).

Thanks in advance,

Ankit