Retry by specifying a transport procotol:

– from the TVideoGrabber SDK
by adding at the end of the URL one of the following options:
“>rtsp_transport=http”
“>rtsp_transport=tcp”
“>rtsp_transport=udp_multicast”
“>rtsp_transport=”udp”

– or from the filter interface by invoking:
RTSPFilterConfig.SetInt (RTSP_Source_RTSPTransport_int, Option)
with Option as integer having one of the following values:
1: tcp
2: udp
3: http
4: udp_multicast

If this does not help please contact us.