[web2py] FORM.accepts fails on dev_appserver

[Carl]

I have the following code which runs fine on web2py but dev_appserver.py 
the call to greetform returns False not True

greetform = FORM( INPUT(_name='email', requires=IS_EMAIL()),
               LABEL(''),INPUT(_type='submit', _value=T('send')),
               _name='greetings')

if greetform.accepts(request.vars, session, formname='greetings', 
keepvalues=True):
    fab=True
else:
    fab=False

So... under dev_appserver.py, when a user submits the form, fab it set to 
False. Running straight Web2py, fab is set to True.

I'm baffled.