fire_plugin_hooks function

The following should result in some plugin code being appended to my items/show.php template:
<?php fire_plugin_hook('public_items_show', array('item' => $item)); ?>

Instead it causes an error (despite the fact that I enabled error debugging in .htaccess and config.ini, I'm not getting detailed error messages).

I have both DocsViewer and Geolocation enabled so they should both automatically appear in the item record right?

If I'm using an invalid parameter, where might I find the correct one(s)?

ReadTheDocs: fire_plugin_hook() is not entirely helpful in this regard.

I notice that the following is used in some recent shipped themes:

<?php fire_plugin_hook('public_items_show', array('item' => $item, 'view'=> $this)); ?>

Adding the view option results in no error on most pages (where no plugin data should be appended), but a fatal error on pages where the DocsViewer or Geolocation plugin has data to add.

So something in my template is breaking this functionality. I've got some custom loops that look for specific item types, but I'm not entirely sure where the conflict is happening. Any guesses where I might look?

The 'view' option should be there -- both plugins use it -- which only makes the mystery greater.

Is there any error message at all, or just a white screen, or something else?

Just the standard styled Omeka error message. Not sure why it's not giving me details.

Here's the code for the whole page:

(It's old and admittedly kind inefficient, esp. after being lazily re-worked for Omeka 2.0, but I haven't had time to totally rewrite it just yet...)

There appears to be an undocumented dependency:

Adding fire_plugin_hook('public_header') to header.php solves this issue.