Unable to locate the model you have specified

I know, not again.

The zip file I extracted from says iot is version 3.0.4 though it is reporting CodeIgniter Version 2.1.3 on the home page.

Directory of models folder:

Code:

03/10/2016  04:55 PM    <DIR>          .
03/10/2016  04:55 PM    <DIR>          ..
03/10/2016  04:06 PM             5,016 Crud_m.php
10/05/2013  11:55 AM               114 index.html
03/10/2016  04:55 PM               358 Schemavesion_m.php
              3 File(s)          5,488 bytes
              2 Dir(s)  309,419,139,072 bytes free

Crud_m.php -

Code:

<?php
class Crud_m extends CI_model
{
   private $s_table;
   
/**
* Contructor
*/
   function __construct ()
   {
       parent::__construct();
   }

/**
*    getTable - returns the table we are dealing with
*/
   function getTable()
   {
       return $this->s_table;
   }

/**
*    setTable - sets the table we are dealing with
*/
   function setTable($s_page)
   {
       $this->s_table = $s_page;
       return $this->s_table;
   }
...
}

Schemaversion_m.php

Code:

<?php
class Schemaversion_m extends crud_m
{
   
/**
* Contructor
*/
   function __construct ()
   {
       parent::__construct();
       parent::setTable('schema_version');
   }

/**
* Version - get schema verison
*/
   function version ()
   {
       $data_a = parent::get();
   }

   
}

Controller -

Code:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Database extends CI_Controller {

/**
* Contructor
*/
 public function __construct()
 {
   parent::__construct();
 }

/**
* Index - Root function
*/
   public function index()
   {
       $this->load->view('welcome_message');
   }
   
/**
* Version - display schema version
*/
   public function version()
   {
       $this->load->model('Crud_m');
       $this->load->model('Schemaversion_m');
       echo 'Schema version is '.'<br/>';
   }
   
}

Executing the version function returns the following error

Code:

An Error Was Encountered

Unable to locate the model you have specified: schemaversion_m

The Crud_m model loads, Schemaversion_m doesn't