Upgrade to 2.3.1 Custom plugin failure -- using all MyISAM tables

We recently upgraded from 2.1.3 to 2.3.1 and a custom plugin is now failing. The custom plugin extends Omeka_Plugin_AbstractPlugin and is a creation of a simple search form. I do not see any tables created by the custom plugin. I noticed that all of our tables for Omeka are all MyISAM. Could the failure be related to the use of MyISAM table type? Is there an upgrade path for custom plugins? Seach the docs, but wasn't sure exactly where to look.

Also, the custom form is a helper that extends Zend_View_helperForm, if that helps.

class CustomSearch_View_Helper_CustomForm extends Zend_View_Helper_Form {
public function customForm()
$form = new Omeka_Form();
->setAttrib('name', 'advanced');

What do you mean when you say this plugin is "failing"?

This hook at the top of custom theme index.php is returning no data:
<?php fire_plugin_hook('public_items_search', array('view' => $this)); ?>

'public_items_search' is an array element in the plugin.

Maybe this will help:
class CustomSearch extends Omeka_Plugin_AbstractPlugin

protected $_filters = array('admin_navigation_main', 'public_navigation_main', 'public_items_search', 'public_items_browse');

protected $_hooks = array('install', 'uninstall');

protected $_options = array();

public function hookInitialize()
get_view()->addHelperPath(dirname(__FILE__) . '/views/helpers', 'CustomSearch_View_Helper_');

Update: I converted all tables in the Omeka database to the INNODB engine and the plugin is still not returning data for our home page custom theme. We have a Slider on the homepage that displays one image and its data. You can see pre-update version at: https://www.tsl.texas.gov/apps/arc/fireinsurancemaps/. Let me know what you think.