Error accessing Model Codeigniter

I've checked and all my calls are correct. The code ran on Windows and transferred it to Ubuntu. After the download gives this error:

  

An Error Was Encountered

     

Unable to locate the model you have specified: crudmodel

The model in question (crudModel.php):

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

class CrudModel extends CI_Model {

    public function __construct()
    {       
        parent::__construct();
    }

    public function add($tabela= NULL, $dados= NULL){
        if ($this->db->insert($tabela, $dados)){
            return TRUE;
        }
        else{
            return FALSE;
        }
    }

    public function delete($tabela= NULL, $dados= NULL){
        $this->db->where('id', $dados);
        if ($this->db->delete($tabela)){
            return TRUE;
        }
        else return FALSE;  
    }

    public function read($tabela= NULL){

        $result= $this->db->get($tabela);
        return $result;     
    }

    public function buscaDados($tabela= NULL, $dados= NULL){

        if ($tabela!= NULL && $dados!= NULL){
            $this->db->where('id', $dados);
            if ($this->db->update($tabela)){
                return TRUE;
            }
            else return FALSE;  
        }
        else return FALSE;  
    }

    public function update($tabela= NULL, $dados= NULL){

        if ($tabela!= NULL && $dados!= NULL){
            return $result= $this->db->get_where($tabela, $dados);
        }
        else return FALSE;      
    }
}

From what I've seen, the problem is in autoload ... but I do not know how to hit that.

Autoload:

$autoload['packages'] = array();
$autoload['libraries'] = array('form_validation', 'session', 'database', 'table', );
$autoload['helper'] = array('url', 'form', 'html', 'file', );
$autoload['model'] = array('crudModel', 'sessionModel', );

Example of calling the method of the model class:

$dados= $this->crudModel->buscaDados('usuario',$dados);