Firefox在www.localhost.com找不到服务器。

When i run my asp.net application it shows error on web page "Firefox can't find the server at WWW.localhost.com" I am using Visual Studio 2010 Ultimate and Windows 7 OS and Browser Firefox Please Give me super and Permanent solution as much as fast because i have to complete my asp.net project so soonWhen i run my asp.net application it shows erro