Try copying the code from the page source.
I'm not sure why but if you copy it from the form it fails but if you copy it from the page source it works.
I copied both in to the html editor and couldn't see any differences. There must a be a character that is getting messed up but is still appearing correct in the editor. I used a code converter to make the code postable.
Very strange.

http://horgenhonning.net/date/

Got it working! Thanks, Eric!

Cool stuff.

Obviously someone has tested the date picker form I made, because I got a mail from it. I'll hurry taking it down before the spammers discover it

On my form examples I don't enter anything for confirmation or notification.