I think this forum thread asks a similar question:
http://forum.videohelp.com/threads/336253-Capturing-or-copying-from-DirectTV-DVD-HR-24-100
They're talking about a HR24-100 - is that the same model or do you have a newer one?
Short answer from that forum is that you can't do it unless you "play" the content from the PVR and live capture/record it on your PC, which is a terrible solution IMHO. It has an ethernet, but that only streams content, it doesn't allow you access to the source files. Having said that, if you can stream the media from the device, would that solve your problem? The device allows you to add an external e-sata drive to expand access, but apparently it encodes all the content with the chief purpose of stopping...