If you ever wondered how to change the page.tpl.php for a custom content type you've found out that by default Drupal 6 doesn't know how to do it.

It's "fixed" easily by adding the following code:

/**
* Override or insert PHPTemplate variables into the templates.
*/
function phptemplate_preprocess_page(&$vars) {
// Add per content type pages
if (isset($vars['node'])) {
// Add template naming suggestion. It should alway use hyphens.
// If node type is "custom_news", it will pickup "page-custom-news.tpl.php".