Symptom: extremely slow page load time for admin publish/edit post page, taking over 3 minutes, and stalling after the H4 Podcasting Files header. During the page load, it is impossible to save text or embed images and media.
In case someone else has this problem, it seems to have been caused by PHP 4.x. The solution was to upgrade to PHP 5.x
I'm now using 5.2.9 and the problem went away immediately.
The information that PHP 5.x is required should be in the plugin details.