While I had Pd working last week, something seems to have happened and now I'm getting errors that I can't work out right now. I'll be out of town for a few days, but will look at it again when I get back. I'm sorry I couldn't be of more help this time around! Hopefully by the next release, my set up will be a bit more stable. :)
If anyone is curious, Pd is repeatedly printing "raspberrypi pd[607]: tried but couldn't sync A/D/A". Since it seems there could be several causes and the solution is not obvious, I'm going to have to put off solving it for now.