Fix issue with message box for non ENG COM3D2

MultipleMaids/CM3D2/MultipleMaids/Plugin/MultipleMaids.Gui.cs

@@ -8859,8 +8859,11 @@ namespace CM3D2.MultipleMaids.Plugin
 
                 MessageClass inst = new MessageClass(gameObject1, messageWindowMgr);
                 // Fix for ENG version: reconfigure MessageClass to behave as in JP game
-                inst.subtitles_manager_.visible = false;
-                inst.subtitles_manager_ = null;
+                if (inst.subtitles_manager_ != null)
+                {
+                    inst.subtitles_manager_.visible = false;
+                    inst.subtitles_manager_ = null;
+                }
                 component.gameObject.SetActive(true);
                 nameComponent.gameObject.SetActive(true);
                 UTY.GetChildObject(gameObject1, "MessageViewer/MsgParent/MessageBox", false).SetActive(true);