"File Not Found" when "Design your form"


I've just started with a small POC using this Form Generator. When clicking on "Design your form" i receive an exception.
The callstack suggests it is unable to create SPSite object. Probably this part of the code:
    private string SetAudience()
        string url = Request.QueryString["url"];
        using (SPSite site = new SPSite(url))
The Url when editting the page is: https://xxx.mac.nl/Pages/default.aspx?DualLayout_ShowInEditMode=true
This is the Url behind the "Design your form"-link: "https://xxx.mac.nl/_layouts/SFG/SFGDesignForm.aspx?id=g_74075c7d_29ee_4e8f_bba7_a941e443c214&url=http://xxx.mac.nl/Pages/default.aspx &uid=cdb8d7c1-3538-4adb-8d00-e58da2e3e46f"
My SiteCollection is ONLY hosted under "httpS://xxx.mac.nl/". Can that maybe be the cause of the error?
File Not Found. at Microsoft.SharePoint.SPSite..ctor(SPFarm farm, Uri requestUri, Boolean contextSite, SPUserToken userToken)
at Microsoft.SharePoint.SPSite..ctor(String requestUrl)
at SFG.SFGDesignForm.SetAudience()
at SFG.SFGDesignForm.Page_Load(Object sender, EventArgs e)
at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e)
at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e)
at System.Web.UI.Control.OnLoad(EventArgs e)
at System.Web.UI.Control.LoadRecursive()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)


maiden123 wrote Nov 15, 2011 at 5:44 PM

yups same here.. the design your form gives file not found!

wrote Feb 14, 2013 at 7:24 PM