The Kindle can browse perlybook.org directly, but download fails. It says that it can only dowload the format "MOBI" ... which perlybook offers. Maybe the file-ending needs to be uppercase? This would be stupid but worth a try...
solved in commit b31abb3
thanks to http://www.mobileread.com/forums/showthread.php?t=99550
I can download it now, and it displays at the bottom of the starting page... but I can't open it!