Public Wi-Fi networks can be very restrictive. Often, they will only allow web browsing and email.
One thing you can try is to enable the "Auto-Config Router" option in iCamSource. That will attempt to use UPnP to open a port in the router so that your computer can communicate with remote networks. It's most likely that the Hotel network won't allow the Auto-Config Router option to work, but it's worth trying.
Also, please quit or disable all firewall software on the computer running iCamSource (temporarily) to see if iCam starts working. If it does, we can configure the firewall to work with iCam.