Allowed sharing firewall does not seem to work?

Hi. I have the ESET-669 firewalls on our PCs set to Automatic mode, and I'd like to keep it that way. Under Personal firewall -> Rules and zones -> Settings, I have set Allowed sharing, which works just fine between our PCs which have private/local/static IP addresses behind our router -- the public side is connected via DSL.

I just installed TiVo Desktop-2.6.2 Plus, and TiVo on our TV, which also has a private/local static IP address behind our router. However, as confirmed with TiVo tech support, TiVo/TV can only see the TiVo desktop on one of the PCs when the ESET firewall is disabled? Otherwise, with firewall enabled, TiVo/TV does not recognize the PC/Server at the IP address on the PC with the Desktop?

I do not understand why the TiVo cannot interact under Allow sharing? If I keep Allow sharing, I do not see how to add the TiVo executables to any other sub-menu, e.g., Application modification detection, etc.??

Thanks for any suggestions.

Lester