diff --git a/components/geckoport/nsXPCOM.pas b/components/geckoport/nsXPCOM.pas
index 0ad000fef..62b1b6184 100644
--- a/components/geckoport/nsXPCOM.pas
+++ b/components/geckoport/nsXPCOM.pas
@@ -3979,6 +3979,12 @@ type
     procedure OnSecurityChange(aWebProgress: nsIWebProgress; aRequest: nsIRequest; aState: PRUint32); safecall;
   end;
 
+  nsIWebProgressListener2 = interface(nsISupports)
+  ['{dde39de0-e4e0-11da-8ad9-0800200c9a66}']
+    procedure OnProgressChange64(aWebProgress: nsIWebProgress; aRequest: nsIRequest; aCurSelfProgress: PRInt64; aMaxSelfProgress: PRInt64; aCurTotalProgress: PRInt64; aMaxTotalProgress: PRInt64); safecall;
+    function  onRefreshAttempted(aWebProgress: nsIWebProgress; aRefreshURI: nsIURI; aMillis: PRInt32; aSameURI: PRBool): PRBool; safecall;
+  end;
+
   nsIWindowCreator = interface(nsISupports)
   ['{30465632-a777-44cc-90f9-8145475ef999}']
     function CreateChromeWindow(parent: nsIWebBrowserChrome; chromeFlags: PRUint32): nsIWebBrowserChrome; safecall;
diff --git a/components/geckoport/nsXPCOMGlue.pas b/components/geckoport/nsXPCOMGlue.pas
index 7224a2234..a9fc37acd 100644
--- a/components/geckoport/nsXPCOMGlue.pas
+++ b/components/geckoport/nsXPCOMGlue.pas
@@ -426,9 +426,17 @@ var
   rv: nsresult;
 begin
   rv := FSupports.QueryInterface(uuid, Intf);
-  if NS_FAILED(rv) then
+  if NS_FAILED(rv) then begin
+    //This is not a catastrophic error, so no exception is needed.
+    //In example the uuid {DDE39DE0-E4E0-11DA-8AD9-0800200C9A66} request
+    //for a nsIWebProgressListener2. Just answering nothing does not
+    //produce an "error".
+    {$IFDEF DEBUG}
+    OutputDebugString(GUIDToString(uuid);
+    {$ENDIF}
     //raise EGeckoError.Create('QueryReference Error');
-    System.Error(reIntfCastError);
+    //System.Error(reIntfCastError);
+  end;
 end;
 
 destructor TSupportsWeakReference.Destroy;