I’ve discovered the issue, although I don’t know how to resolve it.
Due to some other Buddypress issues, I’ve recently moved my WP install from a sub dir into the root. It seems that while WP is upgrading and installing files in the root directory install, the plugins are still being pulled from the old sub directory.
What happened this weekend was I upgraded to the latest podpress, and while the plugin files were upgraded in the proper install directory (root), WP is still pulling the plugins from the old install.
Now this is a whole new batch of problems …