In my status report on November 1st, I reported that I had written a script to fix invalid download links. Turns out my script doesn't work as well as I had hoped. For example, I only fixed 30 of the 120 or so PyCon 2010 videos. I'm working on fixing it so that I can more programatically work through all the videos on Python Miro Community and update download links.
I'm really sorry about this. Not having working download links and podcast feeds sucks.