Here is another one with the same problem (has full example):
http://stackoverflow.com/questions/19478692/gstreamer-video-playback-fails-in-windows-at-second-play-time-when-the-video-fi

The way I do it is basically:

    GstElement* pipeline;
    gst_init(NULL, NULL);
    pipeline = gst_element_factory_make("playbin", "player");
    GstElement *sink = gst_element_factory_make ("d3dvideosink","video-sink");
    g_object_set(GST_OBJECT(pipeline),"video-sink",sink,NULL);
    g_object_set(GST_OBJECT(pipeline), "uri",g_filename_to_uri(fileName.c_str(),
                 NULL, NULL), NULL);
    g_object_set(GST_OBJECT(sink), "force-aspect-ratio", TRUE, NULL);
	gst_object_unref(sink);

and deallocating with: 

    gst_element_set_state (pipeline, GST_STATE_NULL);
    gst_object_unref (GST_OBJECT (pipeline));

I made sure the refcount is 0 there so there's no memory leak. The next time I go through the same procedure I get the error.