Wait .... is the "small box" the H25, or something connected to the H25? Confused.
I assume you did not have a Genie DVR before you got the HR44, right? Therefore, somewhere, you had to have a "Cinema Connection Kit" device to bridge your home network to the coax cable network. That box might be hidden somewhere. If that box is still connected, then you can't use the HR44's WiFi connection to your home network. It's one or the other.
You might try disabling your HR44's WiFi connection and see what happens. If you still have Internet access, and your WHDVR sharing starts working, then you're good to go.