AviDemux does not recognize AC3

I've had great luck with AviDemux in the past, but recently I reinstalled XP Service Pack 2, and now Avidemux cannot edit MPEG2 Program Stream files. I've installed ffdshow codecs as well as AC3filter. When I open the files in AviDemux and view the Information, the Audio portion is grayed out. When I try to save (Copy video and Copy audio), I get the error message "There is no audio track". I record these files from broadcast with an AverTV Combo PCIe. They play fine in Media Player Classic and Media Player, and GSpot recognizes the AC3 audio. Similarly to AviDemux, the files won't save in Womble MPEG-VCR either. As I said, I've edited these same files before with no problem. Any ideas?

Here's a sample MPEG2 file:

What you can try: 1. Try to run your files trough ProjectX and see if it helps 2. Try open your files trough Avisynth + DGIndex