It looks like you may have the config issue at your end with firewall in place. if u can provide the config and remove the ip address and the passwords from it i guess i could help. In the mean time try disabling the fixup for rtsp.
The fixup protocol rtsp command lets PIX Firewall pass Real Time Streaming Protocol (RTSP) packets. RTSP is used by RealAudio, RealNetworks, Apple QuickTime 4, RealPlayer, and Cisco IP/TV connections.
If you are using Cisco IP/TV, use RTSP TCP port 554 and TCP 8554:
fixup protocol rtsp 554
fixup protocol rtsp 8554
The following restrictions apply to the fixup protocol rtsp command:
1. This PIX Firewall will not fix RTSP messages passing through UDP ports.
2. PAT is not supported with the fixup protocol rtsp command.
3. PIX Firewall does not have the ability to recognize HTTP cloaking where RTSP messages are hidden in the HTTP messages.
4. PIX Firewall cannot perform NAT on RTSP messages because the embedded IP addresses are contained in the SDP files as part of HTTP or RTSP messages. Packets could be fragmented and PIX Firewall cannot perform NAT on fragmented packets.
5. With Cisco IP/TV, the number of NATs the PIX Firewall performs on the SDP part of the message is proportional to the number of program listings in the Content Manager (each program listing can have at least six embedded IP addresses).
6. You can configure NAT for Apple QuickTime 4 or RealPlayer. Cisco IP/TV only works with NAT if the Viewer and Content Manager are on the outside network and the server is on the inside network.
7. When using RealPlayer, it is important to properly configure transport mode. For the PIX Firewall, add an access-list command statement from the server to the client or vice versa. For RealPlayer, change transport mode by clicking Options>Preferences>Transport>RTSP Settings.
If using TCP mode on the RealPlayer, select the Use TCP to Connect to Server and Attempt to use TCP for all content check boxes. On the PIX Firewall, there is no need to configure the fixup.
If using UDP mode on the RealPlayer, select the Use TCP to Connect to Server and Attempt to use UDP for static content check boxes, and for live content not available via Multicast. On the PIX Firewall, add a fixup protocol rtsp port command statement.