Are your iMac, and Tivo on the same subnet? have you checked any firewall setting on the iMac?
I have all our tivo's able to view our iPhoto libraries, and iTunes libraries, with no issue. so it is probably just a simple issue/setting within your LAN.
I have all our tivo's able to view our iPhoto libraries, and iTunes libraries, with no issue. so it is probably just a simple issue/setting within your LAN.