Photonic gives "Not found" error

I have a dozen or so pages on my Wordpress blog that display SmugMug galleries. I had no problem setting them up an editing them, but I lost that ability today. After the "Choose Type of Gallery" dialog, I get a "Not found" error. Same error if I try to create a new gallery. I have posted to Wordpress Forum, too, but thought I'd try here just in case there's an easy fix. I'm new to this. Here's an example gallery. (All galleries are working, I just can't edit them.)