Don't try to make file associations starting with Vista

At some point the registry key setting stopped working, not sure as of what Windows version. But this will avoid the 'Failed to set data for '' ' error

Main.pas

@@ -1279,7 +1279,7 @@ begin
   FMinToTray := true;
   FExportSheets := false;
 
-  MakeFileAssociations;
+  if Win32MajorVersion < 6 then MakeFileAssociations;
 end;
 
 procedure TMainForm.SpeedButton1Click(Sender: TObject);