DVD recorder and cable

I bought an RCA DVD recorder a few months ago to replace a VCR that broke. Just yesterday I tried to record a program off of my digital cable box, and the recorder gave me a message saying that “The audio video content you are trying to copy cannot legally be copied. It has been protected to prevent copies.” I’m now getting this message from most but not all channels, including some channels that I was previously able to record.

For instance, I recorded the first three episodes of Deadwood off HBO last week when they ran them back-to-back. Now I can’t record anything off any of the HBO channels. Just earlier today I was able to record a sample off of TMC, but now, a few hours later, I can’t.

Some of the basic cable channels are “protected” too.

I can still record the non-digital channels through the recorder’s tuner (as opposed to using the direct video input, which is how I record the digital channels), but this is a real pain in the butt. I want to be able to record everything. (This is all strictly for my own personal, time-shifting purposes, of course.)

Does anyone know about this copy protection scheme, and why it should be showing up so erratically? (N.B. I’m not asking how to defeat it, just trying to learn more about it and figure out how and when I should expect it to appear.)

Thanks.

C’mon, no one knows anything about this???