diff --git a/src/gui_builder.cc b/src/gui_builder.cc
index d2c9d35..4fe2f57 100644
--- a/src/gui_builder.cc
+++ b/src/gui_builder.cc
@@ -73,6 +73,7 @@
 using namespace sgpem;
 using Gnome::Glade::Xml;
 
+
 void
 GuiBuilder::on_edit_preferences_activate()
 {
@@ -149,7 +150,7 @@ GuiBuilder::on_file_new_activate()
 
  	sim.stop();
   history.clear();
-  _filename = "";
+  set_filename();
 }
 
 
@@ -201,7 +202,7 @@ GuiBuilder::on_file_open_activate()
     int result = dialog.run();
     if(result==Gtk::RESPONSE_OK)
     {
-      _filename = dialog.get_filename();
+      set_filename(dialog.get_filename());
       sim.stop(); // It would work anyhow, but it'd look strange
       History& history = sim.get_history();
       serializer.restore_snapshot(_filename, history);
@@ -211,13 +212,18 @@ GuiBuilder::on_file_open_activate()
   }
   catch (std::out_of_range e)
   {
-    // FIXME: this should be an error dialog
-    msg = _("ERROR: No registered serializer available");
+     Gtk::MessageDialog error(get_initial_window(),
+                        _("<b>No serializer available.</b>\nThere's no registered serializer. Please check the loaded plugins."),
+                        true, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_OK, true);
+     error.run();
+     msg = _("ERROR: No registered serializer available");
   }
   catch (SerializerError e)
   {
-    // FIXME: this should be an error dialog
+    Gtk::MessageDialog error(get_initial_window(), e.what(), true, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_OK, true);
+    error.run(); 
     msg = _("ERROR: ") + Glib::ustring(e.what());
+    set_filename();
   }
   if(!msg.empty())
   {
@@ -254,13 +260,17 @@ GuiBuilder::on_file_save_activate()
     }
   catch (std::out_of_range e)
     {
-      // FIXME: this should be an error dialog
+      Gtk::MessageDialog error(get_initial_window(),
+                        _("<b>No serializer available.</b>\nThere's no registered serializer. Please check the loaded plugins."),
+                        true, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_OK, true);
+      error.run();
       msg = _("ERROR: No registered serializer available");
     }
   catch (SerializerError e)
     {
-      // FIXME: this should be an error dialog
-      msg = _("ERROR: ") + Glib::ustring(e.what());
+     Gtk::MessageDialog error(get_initial_window(), e.what(), true, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_OK, true);
+     error.run();
+     msg = _("ERROR: ") + Glib::ustring(e.what());
     }
   
   if(!msg.empty())
@@ -309,12 +319,14 @@ GuiBuilder::on_file_saveas_activate()
     int result = dialog.run();
     if(result==Gtk::RESPONSE_OK)
     {
-      _filename = dialog.get_filename();
+      std::string filename = dialog.get_filename();
 
       // Append standard extension if none (or a different one) is provided
       std::string ext = std::string(".") + serializer.get_filename_extension();
-      if(_filename.size() < ext.size() || _filename.substr(_filename.size() - ext.size()) != ext)
-        _filename += ext;
+      if(filename.size() < ext.size() || filename.substr(filename.size() - ext.size()) != ext)
+        filename += ext;
+
+      set_filename(filename);
 
       serializer.save_snapshot(_filename, history);
 
@@ -324,13 +336,18 @@ GuiBuilder::on_file_saveas_activate()
   }
   catch (std::out_of_range e)
   {
-    // FIXME: This should be an error dialog:
+    Gtk::MessageDialog error(get_initial_window(),
+                              _("<b>No serializer available.</b>\nThere's no registered serializer. Please check the loaded plugins."),
+                              true, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_OK, true);
+    error.run();
     msg = _("ERROR: No registered serializer available");
   }
   catch (SerializerError e)
   {
-    // FIXME: This should be an error dialog:
+    Gtk::MessageDialog error(get_initial_window(), e.what(), true, Gtk::MESSAGE_ERROR, Gtk::BUTTONS_OK, true);
+    error.run();
     msg = _("ERROR: ") + Glib::ustring(e.what());
+    set_filename();
   }
   
   if(!msg.empty())
@@ -543,6 +560,19 @@ GuiBuilder::ask_save()
 }
 
 
+void
+GuiBuilder::set_filename(const std::string& filename)
+{
+  static const Glib::ustring default_title = get_initial_window().get_title();
+  Glib::ustring title;
+  _filename = filename;
+  if(!_filename.empty())
+    title = Glib::path_get_basename(_filename) + " - ";
+  title += default_title;
+  get_initial_window().set_title(title);
+}
+
+
 GuiBuilder::GuiBuilder(const std::string& gladefile)
   : _refXml(Xml::create(gladefile)), _controller(Simulation::get_instance(), _refXml),
     _holt_container(Simulation::get_instance()),
diff --git a/src/gui_builder.hh b/src/gui_builder.hh
index 6bfc282..d235515 100644
--- a/src/gui_builder.hh
+++ b/src/gui_builder.hh
@@ -87,6 +87,7 @@ namespace sgpem
     SimulationWidget*              _simulation_widget;
     bool                           _show_threads;
 
+    void set_filename(const std::string& filename = "");
     void ask_save();
   };