"The web page cant be found" error is coming after I kept my sharepoint 2010 FBA site ideal for some time.

"The web page cant be found" error is coming after I kept my sharepoint FBA site ideal for some time. I've written the code in my master page for redirecting to home page after the session expires, but its not redirecting to home page but simply displays "The web page cant be found". Do I need to write/set any thing in sharepoint to not to get this error? pls give me the solution.
Thank & Regards:
Venky