It may be that Chromecast relies on multicasting, and in the home routers from Netgear, it is disabled by default. To enable it, simply log in to the router, go to "WAN Setup" and make sure that "Disable IGMP Proxying" is not enabled (uncheck it). Apply the settings, restart your router and devices and give it another go now.
Okay, got it to work but only after getting the same error messages then selecting to install by Chromecast through the web. They had me manually connect to Chromecast on my tablet WiFi, then during the process, reconnect my tablet to my home network. Weird as my tablet saw Chromecast when connected to my home network in the normal install process. Now let's see if it will work on all my other TV's. Thanks for he replies - will add G2 if its meaningful.