gboolean
cmc_manager_open (CmcManager *cm, const gchar *uri, DBusGMethodInvocation *context)
{
    guint handle = 0;

    g_debug ("opening uri %s", uri);
    g_debug ("sender %s", dbus_g_method_get_sender (context)); // IT CRASHES HERE, or calling dbus_g_method_return if i comment this line

    dbus_g_method_return (context, handle);

    return TRUE;
}

============================= CUT HERE ==================

Here is the definition of the method on the xml

    <method name="Open">
      <arg type="s" name="uri" direction="in"/>
      <arg type="u" name="handle" direction="out"/>
    </method>