Just picked up an explorer (cisco) 4742hdc at Goodwill

I was hoping to use it to get my HD channels and HBO in my room. I have a cox digital DVR in my front room which picks up all my HD and pay channels. The TV in my bedroom just gets the basic stuff, none of my pay channels show up. So I've got the 4742 plugged in and set up in my bedroom. I can get the cox program guide and view local HD channels only. When I try to view say Spike, or CNN or any HBO channels I get error 1.1.3, This is a subscription service.

Am I really going to have to pay extra to get my channels in another room when I already pay for the channels?

Thanks for the help

PS

Got the box for $6.99.