In computer networking, port forwarding or port mapping is an application of network address translation (NAT) that redirects a communication equest from one address and port number combination to another while the packets are traversing a network gateway, such as a router or firewall. This technique is most commonly used to make services on a host residing on a protected or masqueraded (internal) network available to hosts on the opposite side of the gateway (external network), by remapping the destination IP address and port number of the communication to an internal host. Wikipedia
You have to forward the TCP Port 8080 (Keyword in the manual of your router: Port forwarding) to use the direc streaming to your website with Restreamer. Only if the port is forwarded the connection between your video player and Datarhei to will be successful.