[support] hook_form_alter() and custom cck forms

I have a custom cck form in which I want to alter some of he fields on the form. When I try the code on the forms that come with drupal e.g user_profile_form, my code(at least return print_r($form);) works.

When I "view" my html source for my custom cck form, I get the souce below for the form id is "node-form" as you can see <form action="/node/add/my-custom-form" accept-charset="UTF-8" method="post" id="node-form" enctype="multipart/form-data">

my hook_form_alter code is as below

function fielddisable_form_alter(&$form, $form_state, $form_id) {

switch ($form_id) {

case 'node_form':

return print_r($form);

break;

} }

What Am I doing wrong?