Well, I fixed it by doing an ugly hack - but it works. The trick was to use an absolute path on the local machine (a path that starts with "/" instead of "http://";). Unfortunately it means that my pathname is very long and if I ever move things around I'll have to remember to update that. It would be much better if bloginfo could return this kind of absolute path.
If you ever figure this out, let me know so I can clean up the code. Thanks again, John
