arduarn:
Take AWOL's hint and research the access methods for data in flash memory. Start here:
http://www.atmel.com/webdoc/avrlibcreferencemanual/pgmspace.html
Hmmm, well I've now looked into these access methods and tried them out, but haven't had much luck.
Is this definitely the problem? I ask because if I remove the PROGMEM command entirely, I still can't get the correct result.