Dish stores programming in perfect digital format, therefore the content providers do not want Dish to allow file transfer for dvd burning. Tivo records a lesser quality mpeg2 file so they are allowed to allow file transfers. Easiest solutions? Hook up OTA to your HTPC and that way all your dvr files are already on your computer.
There is also the dishrip Yahoo group if you want to do it faster than real time, and maintain the original quality. That process it not easy, though, since you must temporarily remove your disk from the IRD.