Please describe the problem:
When I create multiple playbin elements in the paused or ready state quickly after each other, things get pretty messed up.  Most of the time, only one of the files actually can be heard (the other seems to "play" silently), but once in a while I get random assertion failues, crashes, etc.

If there is a one second pause between the individual element's creation and setup, all files can be heard playing.

Steps to reproduce:
Run the following example program, for example with two file:///file1.ogg and file:///file2.ogg.
#include <gst/gst.h>
GMainLoop *loop;
static gboolean
my_bus_callback (GstBus *bus, GstMessage *message, gpointer data)
{
  switch (GST_MESSAGE_TYPE (message))
    {
    case GST_MESSAGE_ERROR:
      {
	GError *err;
	gchar *debug;
	
	gst_message_parse_error (message, &err, &debug);
	g_print ("Error: %s\n", err->message);
	g_error_free (err);
	g_free (debug);
	
	g_main_quit (loop);
	break;
      }

    case GST_MESSAGE_EOS:
      /* end-of-stream */
      g_main_quit (loop);
      break;

    default:
      /* unhandled message */
      break;
  }

  /* We want to be notified again the next time there is a message on
     the bus, so returning TRUE (FALSE means we want to stop watching
     for messages on the bus and our callback should not be called
     again).  */
  return TRUE;
}

int
main (int argc, char *argv[])
{
  gst_init (&argc, &argv);

  loop = g_main_loop_new (NULL, FALSE);

  argc--;
  argv++;
  while (argc-- > 0)
    {
      GstElement *play;
      GstBus *bus;
	  
      play = gst_element_factory_make ("playbin", "play");
      g_object_set (G_OBJECT (play), "uri", argv[0], NULL);
      argv++;

      bus = gst_pipeline_get_bus (GST_PIPELINE (play));
      gst_bus_add_watch (bus, my_bus_callback, loop);
      gst_object_unref (bus);

      gst_element_set_state (play, GST_STATE_PLAYING);
      // Sleep works around it.
      // sleep (1);
    }

  g_main_loop_run (loop);

  return 0;
}


Actual results:
Most of the time, only one file is heard from the speaker.  Sometimes, various random crashes and assertion failures occur, for example:

* main3: pcm.c:725: snd_pcm_nonblock: Assertion `pcm' failed.

* (main3:16472): GLib-GObject-WARNING **: invalid (NULL) pointer instance

(main3:16472): GLib-GObject-CRITICAL **: g_signal_connect_data: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed

(main3:16472): GLib-GObject-CRITICAL **: g_object_set_data: assertion `G_IS_OBJECT (object)' failed

(main3:16472): GStreamer-CRITICAL **: gst_pad_link_prepare: assertion `GST_IS_PAD (sinkpad)' failed

(main3:16472): GStreamer-CRITICAL **: gst_object_unref: assertion `object != NULL' failed
Error: Internal data stream error.

* (main3:17385): GLib-GObject-WARNING **: IA__g_object_set_valist: object class `GstStreamInfo' has no property named `mute'


Expected results:
What should happen is that both files start playing and are heard.

Does this happen every time?
Yes.

Other information:
sleep(1) after changing the state to PLAYING works around it.