Our Prowler did the same thing . . .
Check the first splitter in the coax line after the bedroom TV (probably behind the wall in the basement).
I found that one wired up backwards (ie.- splitters line in was going to the outside TV outlet and the coax coming down from the bedroom, which should have been going to the input was hooked up to one of the outputs of the splitter).
Splitters are one-way (however, the antenna signal made it through), so with the cable signal coming from upstairs into the output of the splitter, that was the end of the line for the cable signal.
There were some other problems with ours as well, but the above should get you going!