In the latest version of Arduino, the new avr gcc requires that PROGMEM use include the const modifier. This causes a section type conflict error as reported by some users of the shield. As a result, I couldn't get this shield working with my Arduino Duemilanove without this change. Full documentation on what fixed the error can be found here: http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=38003.