Hello, I landed here trying to get PDN to open .CR2 files from my Canon 600D.
I already had the RAW CODEC, downloaded from the Canon support site. I've given the link below. I then installed the RAWload (link below and again link #3 from jim's post) plugin (nothing more from that thread) and started PDN.
Images open right away from within Paint.NET with these two components. I hope this helps, and hasn't duplicated any other work or suggest (I did check, couldn't find anything).
Canon RAW CODEC
RAWLoad
Thanks,
Smiffa