Index: /trunk/include/VBox/dbus-calls.h
===================================================================
--- /trunk/include/VBox/dbus-calls.h	(revision 24072)
+++ /trunk/include/VBox/dbus-calls.h	(revision 24073)
@@ -27,4 +27,6 @@
 /** The following are the symbols which we need from libdbus-1. */
 VBOX_PROXY_STUB(dbus_error_init, void, (DBusError *error),
+                (error))
+VBOX_PROXY_STUB(dbus_error_is_set, dbus_bool_t, (const DBusError *error),
                 (error))
 VBOX_PROXY_STUB(dbus_bus_get, DBusConnection *,
Index: /trunk/src/VBox/Additions/x11/VBoxClient/hostversion.cpp
===================================================================
--- /trunk/src/VBox/Additions/x11/VBoxClient/hostversion.cpp	(revision 24072)
+++ /trunk/src/VBox/Additions/x11/VBoxClient/hostversion.cpp	(revision 24073)
@@ -100,6 +100,16 @@
 
             DBusError err;
-            dbus_connection_send_with_reply_and_block(conn, msg, 30 * 1000, &err);
+            DBusMessage *reply;
+            reply = dbus_connection_send_with_reply_and_block(conn, msg,
+                30 * 1000 /* 30 seconds timeout */, &err);
+            if (dbus_error_is_set(&err))
+            {
+                Log(("D-BUS returned an error while sending the notification: %s", err.message));
+            }
+            else if (reply)
+            {
                 dbus_connection_flush(conn);
+                dbus_message_unref(reply);
+            }
         }
         if (msg != NULL)