Actually it was not an application issue.But the client machine's browser's security settings had to have the webserver's name under trusted site.
so issue got resolved like that.
Now i am hitting another one which is as follows.Actually we have four different machines as i have shown.
Client can not request the page directly from webserver and has to go through MIDTIER. But here is an IFRAME that is executed on the MIDTIER.
<IFRAME servername/Virtual Directory/aspx page height="800" width="800"></IFRAME>
So now the thing is that i log in from client into my application which is residing on Midtier and i try to load that page which has this (<IFRAME servername/Virtual Directory/aspx page height="800" width="800"></IFRAME>) tag and IFRAME is loaded in context to the current page but it is trying to load another page which will be served by the webserver.
The problem here is that Client doesnt have direct access to the webserver so according to my understanding when the IFRAME is loading in the client machine's browser it actually tries to send the credentials of client to the webserver and that is why my request gets no answer from webserver.
I want the request to hit from Client to the midtier and midtier will contact the infra server and infra server will get the response from Webserver and send it to Midtier and then to the Client.
I am clueless.I would so appreciate some help from any one.