If cookies are disabled, the app doesn't maintain its
session; links need to be built using the appropriate
utility class. To reproduce this, disable cookies and
register/log in. You can fill in one page of the form,
but on submission you are kicked back to the login page.
Note - I mispoke in my comment on Matt's weblog, the
app didn't work with cookies disabled, and didnt' seem
to work at first after I enabled them, but eventually did.