Creating a new object subtype is causing crash

I'm modifying page_top to create a different subtype. It works fine, except when I click the pages tab... then I get a crash. It appears to be at mymodname/pages/pages/world.php

I'm changing this part of the code

$content = elgg_list_entities(array(
'type' => 'object',
'subtype' => 'page_top',
'full_view' => false,
));

into:

$content = elgg_list_entities(array(
'type' => 'object',
'subtype' => 'page_world',
'full_view' => false,
));

So I'm trying to get a of list of the page_world objects... but this causes a crash. If I change  page_world, to any type of gibberish, there's no crash... and it says no pages found... so it seems to be detecting my page_world subtype. I have my page_world.php file located in views/default/object

What do I need to do to fix this?

Appreciate any help. Thanks.