ASP Error - The HTTP Headers are already written

While redirecting from a page in asp we get a very common error: The HTTP headers are already written to the client browser. Response object error 'ASP 0156 : 80004005 Header Error /test.asp, line 135 The HTTP headers are already written to the client browser. Any HTTP header modifications must be made before writing page content. The Redirect method of the Response object operates by sending the 302 Object Moved response header,