I updated WordPress to version 3.2 and switched to the Twenty Eleven theme. All my plugins have been updated. Problems with child themes have not been resolved. At this time I just edited the parent theme to insert the code that would normally reside in the child theme. Seems to work just fine. Another mystery of the universe.
Note to self: The code to register custom taxonomies is inserted at the very top of the parent theme’s functions.php. This would be the same order that a child theme’s functions.php would be executed. Why it works there and not in the child theme’s is a mystery.