Error when already logged in

Jul 18, 2008 at 10:53 AM
Edited Jul 18, 2008 at 10:55 AM

My Facebook app is developed with ASP .NET and the Facebook Developer Toolkit.
To install the app, im using an URL like[myApiKey]&v=1.0 and everything works fine.

If I use this URL again and I'm already logged in, then I got the following error:

Invalid parameter
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: Facebook.Exceptions.FacebookException: Invalid parameter

Stack Trace:
[FacebookException: Invalid parameter] Facebook.API.FacebookAPI.ErrorCheck(XmlDocument doc) +900 Facebook.API.FacebookAPI.LoadXMLDocument(String rawXML) +127 Facebook.API.FacebookAPI.CreateSession() +92 Facebook.API.FacebookAPI.CreateSession(String authToken) +15 Facebook.WebControls.BasePageHelper.LoadFBMLPage(FacebookAPI FaceBookAPI, Boolean autoAdd, HttpRequest request, HttpResponse response) +253 Facebook.WebControls.CanvasFBMLBasePage.Page_Load(Object sender, EventArgs e) +83 _App.Page_Load(Object sender, EventArgs e) +67 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +33 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +47 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

Why is that? Anyone got a clue?

Update: if I use[myApiKey]&v=1.0&canvas, there are no problems.
So what is wrong with my application?