Thanks for taking an interest.
Yes, the netmask is the same. My network setup is probably not very clear since it's not very conventional, I've been setting up networks for clients as a consultant for about 25 years so I go back to token ring, IPX/SPX, DECNet, LanMan, Novell and other dinosaur technologies.
I have a cable modem that provides the internet connection and acts as the DHCP and gateway for an Asus WAP running Tomato firmware. The cable modem hands out a single 10.x IP address to the Asus via an ethernet connection to the Asus WAN port; the Asus then acts as the DHCP, DNS and gateway for the wireless-n network, handing out reserved-by-MAC IP addresses in the 192.168.1.x range, strictly speaking 192.168.1.3 and above. This is the conventional part.
I also have a Netgear WAP connected by ethernet over a LAN port, NOT via the WAN port, to the Asus WAP. The Netgear has a hardcoded IP of 192.168.1.2 on the LAN side but has NO address on the WAN side because the WAN port is empty. It is NOT a DHCP server, but it is the WAP for the wireless-g devices and has hardcoded entries for it's DNS server and gateway (192.168.1.1, the Asus WAP). In this configuration, everything on the network sees the Asus as it's DHCP, DNS and gateway server regardless of which SSID and WAP it is physically using to connect to the network (i.e. everything on the network uses 192.168.1.1 for these values). So think of the Netgear WAP as a passthrough connection.
For convenience, the Asus hands out a certain range of addresses for PC/laptops, another range for wireless-n devices like the D* receiver and Android phones and another range for wireless-g devices like an older HP wireless printer.
This all works perfectly for everything except viewing D* from the Flash web client with an older, wireless-g laptop. By "works perfectly" I mean all devices can connect to each other as required for printing, file sharing, admin via web pages etc etc. It works from inside the house and from outside using OpenVPN (one of the reasons for using Tomato) so I can sit in Canada and, on my phone over the internet using OpenVPN, stream my DirecTV channels as if I were sitting at home in the U.S.
One other possible problem is that the wireless-g laptop cannot run the DirecTV2PC client due to graphic card limitations. Could this also be affecting the Flash web client? Maybe, but then the message seems strange i.e. "you must be on the same network as the D* receivers", not "your device cannot play this video" or something. This might really be the problem, just "bad" or "lazy" error trapping and messaging from D* since nothing else makes sense to me at this point.