I am using a Hauppauge 1212 with DirecTV HR-34 (Genie), connected with component video and SPDIF audio, and it is working fine.
If the 1212 is set to SPDIF and for any reason it does not get audio via the digital input, it will blank the video. If you select the RCA audio, it doesn't care and will show (and capture) the video anyway.
I would check the digital audio cable and connection. I don't think DirecTV has disabled anything via any recent update that would cause your problem.