From Facebook Developer Wiki

[edit] IE iframe gotcha solution - missing important information

Your solution to the IE iframe "gotcha" is hiding a lot of important background information, specifically that the header you are suggesting to add - a P3P header - describes the site's privacy policy. This change shouldn't be done by developers without guidance from the site's privacy experts, and should match the site's full privacy policy.

[edit] Error with Web QuickStart

I tried to implement Microsoft's code examples in the Web QuickStart found at http://msdn2.microsoft.com/en-us/express/bb510383.aspx. When I execute the line _fbService.CreateSession(authToken);, a NullReferenceException is thrown. This seems to be coming from Facebook, because the _fbService is an object, and the authToken is an object. So... after tinkering for a while, I found that if I simply trap the error and ignore it, the code works. Not sure exactly what's happening, but hope this helps others:

try
{
   _fbService.CreateSession(authToken);
}
catch ()
{
}

I'm new on asp.net and facebook.net I write new application. I tried on local with successfully but upload a web server and I get this error. Please help me. How do upload on my server?

www.2025arena.com/fb

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

WebException: The remote name could not be resolved: 'api.facebook.com'
System.Net.HttpWebRequest.GetRequestStream() +1532269
Facebook.API.FacebookAPI.GetQueryResponse(String requestUrl, String postString) +220
Facebook.API.FacebookAPI.ExecuteApiCallString(IDictionary`2 parameterDictionary, Boolean useSession) +171
Facebook.API.FacebookAPI.ExecuteApiCall(IDictionary`2 parameterDictionary, Boolean useSession) +43
Facebook.API.FacebookAPI.CreateSession() +156
Facebook.API.FacebookAPI.CreateSession(String authToken) +38
Facebook.Components.FacebookService.CreateSession(String authToken) +47
Default.PageLoad(Object sender, EventArgs e) +282
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +47
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1061

thank you

It worked for me too..