[TYPO3-english] why are flash messages not displaying on some pages

[Calgacus map Brude]

Hi,
I added some flash messages to some pages but they do not show up after a redirect.  Existing pages already have this feature and it works fine there but on the pages I added the exact same code and tag it does not work.  besides adding  code like so:

$this->flashMessageContainer->add('Valid.');
$this->redirect('validate_success');

and a tag like so to the validate_success template 
<f:flashMessages /><br/>

what more is there to making flash messages work?