Внутренняя ошибка WKHTMLTOPDF

У меня есть страница, которая должна отображаться в формате pdf с помощью механизма WKHTMLTOPDF. Когда я нажимаю на ссылку, чтобы загрузить страницу, я получаю эту ошибку:

WKHTMLTOPDF didn't return any data
Error: An Internal Error Has Occurred.

Трассировка стека выглядит следующим образом:

APP\Plugin\CakePdf\Pdf\CakePdf.php строка 234 → WkHtmlToPdfEngine->output()

    }
}

$output = $Engine->output();

APP\Plugin\CakePdf\View\PdfView.php строка 97 → CakePdf->output(string)

печатает это

$this->response->download($this->getFilename()); }

$this->Blocks->set('content', $this->renderer()->output($content));

return $this->Blocks->get('content');

затем распечатывает страницу именно так, как я тоже хочу

CORE\Cake\Controller\Controller.php строка 956 → PdfView->render(null, null)

null
null

CORE\Cake\Routing\Dispatcher.php строка 193 → Controller->render()

 }

        if ($render && $controller->autoRender) {
            $response = $controller->render();

        } elseif ($response->body() === null) {

CORE\Cake\Routing\Dispatcher.php строка 161 → Dispatcher->_invoke(InvoicesController, CakeRequest, CakeResponse)

object(InvoicesController) {
    helpers => array(
        [maximum depth reached]
    )
    uses => array(
        [maximum depth reached]
    )
    paginate => array(
        [maximum depth reached]
    )
    components => array(
        [maximum depth reached]
    )
    name => 'Invoices'
    request => object(CakeRequest) {}
    response => object(CakeResponse) {}
    viewPath => 'Invoices'
    layoutPath => 'pdf'
    viewVars => array(
        [maximum depth reached]
    )
    view => 'view'
    layout => 'adminpdf'
    autoRender => false
    autoLayout => true
    Components => object(ComponentCollection) {}
    viewClass => 'Pdf'
    View => object(PdfView) {}
    ext => '.ctp'
    plugin => null
    cacheAction => false
    passedArgs => array(
        [maximum depth reached]
    )
    scaffold => false
    methods => array(
        [maximum depth reached]
    )
    modelClass => 'Invoice'
    modelKey => 'invoice'
    validationErrors => null
    Toolbar => object(ToolbarComponent) {}
    Session => object(SessionComponent) {}
    Auth => object(AuthComponent) {}
    RequestHandler => object(RequestHandlerComponent) {}
    pdfConfig => array(
        [maximum depth reached]
    )
    Invoice => object(Invoice) {}
    FieldsInvoice => object(FieldsInvoice) {}
    InvoicesItem => object(InvoicesItem) {}
}
object(CakeRequest) {
    params => array(
        [maximum depth reached]
    )
    data => array([maximum depth reached])
    query => array([maximum depth reached])
    url => 'Invoices/view/1.pdf'
    base => '/pra'
    webroot => '/pra/'
    here => '/pra/Invoices/view/1.pdf'
}
object(CakeResponse) {

}

APP\webroot\index.php строка 92 → Dispatcher->dispatch(CakeRequest, CakeResponse)

object(CakeRequest) {
    params => array(
        [maximum depth reached]
    )
    data => array([maximum depth reached])
    query => array([maximum depth reached])
    url => 'Invoices/view/1.pdf'
    base => '/pra'
    webroot => '/pra/'
    here => '/pra/Invoices/view/1.pdf'
}
object(CakeResponse) {

}

вот мой bootstrap.php

<?php
    CakePlugin::loadAll();  
    CakePlugin::load('DebugKit');
     CakePlugin::load('CakePdf', array('bootstrap' => true, 'routes' => true));
     Configure::write('CakePdf', array(
        'engine' => 'CakePdf.WkHtmlToPdf',
        'download'=>true,
        'binary'=>'C:\\Program Files (x86)\\wkhtmltopdf\\wkhtmltopdf.exe'));

    // Enable the Dispatcher filters for plugin assets, and
    // CacheHelper.
    Configure::write('Dispatcher.filters', array(
    'AssetDispatcher',
    'CacheDispatcher'
    ));

    // Add logging configuration.
    CakeLog::config('debug', array(
    'engine' => 'FileLog',
    'types' => array('notice', 'info', 'debug'),
    'file' => 'debug',
    ));
    CakeLog::config('error', array(
    'engine' => 'FileLog',
    'types' => array('warning', 'error', 'critical', 'alert', 'emergency'),
    'file' => 'error',
    ));

представление в моем контроллере

public function view($id = null) {
    $this->set('title_for_layout', 'Invoices');
    $this->set('stylesheet_used', 'homestyle');
    $this->set('image_used', 'eBOXLogoHome.png');
    $this->layout='adminpdf';


    $this->pdfConfig = array('engine' => 'CakePdf.WkHtmlToPdf');

            $this->Invoice->id = $id;
            if (!$this->Invoice->exists()) {
                throw new NotFoundException(__('Invalid invoice'));
            }
            $this->pdfConfig = array(
                'engine'=>'CakePdf.WkHtmlToPdf',
                'orientation' => 'potrait',
                'filename' => 'Invoice_' . $id
            );

            $this->set('invoice', $this->Invoice->read(null, $id));
        //Retrieve Account Id of current User       
        $accountid=$this->Auth->user('account_id');




        //Find all Invoices where $conditions are satisfied
        $invoicedetails=$this->Invoice->find('first', array(
        'conditions' => array('Invoice.id'=>$id)));

        //prints fieldsInvoice details, including invoice and field information
        $invoices=$this->FieldsInvoice->find('all',array(
        'conditions'=>array(
        'invoice_id'=>$id)));

        $itemInvoice=$this->InvoicesItem->find('all',array('conditions'=>array('invoice_id'=>$id)));

        //Set variables
        $this->set('invoicedetails', $invoicedetails);  
        $this->set('invoice', $invoices);   
        $this->set('accountid', $accountid);
        $this->set('itemInvoice', $itemInvoice);

    }



//End of Controller


    }

мой контроллер приложения

class AppController extends Controller {

    public $components = array(
        'DebugKit.Toolbar',
        'Session', 
        'Auth'=>array(
            'loginRedirect'=>array('controller'=>'users', 'action'=>'login'),
            'logoutRedirect'=>array('controller'=>'users', 'action'=>'login'),
            'invoiceRedirect'=>array('controller'=>'invoices', 'action'=>'viewinvoice'),
            'authError'=>"You can't access this page",
            'authorize'=>array('Controller')
        ),
        'RequestHandler'
    );

маршруты.php

 */
    CakePlugin::routes();
    Router::mapResources(array('Invoices'));
    Router::connect('/', array('controller' => 'pages', 'action' => 'display', 'home'));
/**

вот вид, который я хочу отобразить в формате pdf

<div id = "content">
<h2>View Invoice</h2>
                <table id="data">


    <?php

        if($invoicedetails['Invoice']['scheduled']==1)
        {
            $status = 'Scheduled';  
            $fcol = 'Black';
            $bgcol = '#EBD8E8';
            $pay = NULL;
            $dispute = NULL;
        }
        else if($invoicedetails['Invoice']['paid']==1)
        {
            $status = 'Paid';
            $fcol = 'Black';
            $bgcol = '#B9FAEA';
            $pay = NULL;
            $dispute = NULL;
        }
        else if($invoicedetails['Invoice']['sender_id']==$accountid)
        {
            $status = 'Sent';
            $fcol = 'Black';
            $bgcol = '#F8FAC0';
            $pay = NULL;
            $dispute = NULL;
        }
        else if($invoicedetails['Invoice']['receiver_id']==$accountid)
        {
            $status = 'Received';
            $fcol = 'Black';
            $bgcol = '#FAB9B9';
            $pay = $this->Html->link('Pay', array('controller' => 'Invoices','action'=>'pay_admin',$invoicedetails['Invoice']['id'] )) ;
            $dispute = $this->Html->link('Dispute', array('controller' => 'Disputes','action'=>'add_admin',$invoicedetails['Invoice']['id'] ));
        }



    ?>                      
                <tr>
                <th>Sender: </th>
                <td><?php echo $invoicedetails['SenderAccount']['account_name'];?> </td>
                </tr>

                <tr>
                <th>Receiver: </th>
                <td><?php echo $invoicedetails['ReceiverAccount']['account_name'];?> </td>
                </tr>

                <tr>
                <th>Invoice ID: </th>
                <td><?php echo $invoicedetails['Invoice']['id'];?> </td>
                </tr>

                <tr>
                <th>Invoice Date: </th>
                <td><?php echo date('d.m.Y', strtotime($invoicedetails['Invoice']['created'])); ?></td>
                </tr>

                <tr>
                <th>Due Date: </th>
                <td><?php echo date('d.m.Y', strtotime($invoicedetails['Invoice']['expiry_date'])); ?></td>
                </tr>

                <tr>
                <th>Status: </th>
                <td bgcolor='<?php echo $bgcol ?>'><?php echo $status ;?> </td>
                </tr>

                <tr>
                <th>Actions: </th>
                <td><?php echo $pay ?> <?php echo  $dispute ?></td>
                </tr>               


                </table>
                <br>
                <table id="data">
                <tr>
                    <th>Item Name</th>
                    <th>Description</th>
                    <th>Price Per Unit</th>
                    <th>Quantity</th>
                </tr>
                <?php foreach($itemInvoice as $itemInvoices):?>
                <tr>
                <td><?php echo $itemInvoices['Item']['name']; ?></td>
                <td><?php echo $itemInvoices['Item']['description']; ?></td>
                <td>$<?php echo number_format($itemInvoices['Item']['price'], 2, '.', ','); ?></td>
                <td><?php echo $itemInvoices['InvoicesItem']['quantity']; ?></td>
                </tr>
    <?php endforeach; ?>
                </table>

                <br>

                <table id="data">
                <tr>
                    <th>Field Name</th>
                    <th>Entered Value</th>
                </tr>


        <?php foreach($invoice as $invoices):?>
<tr>
<td><?php echo $invoices['Field']['name']; ?> :</td>
<td><?php echo $invoices['FieldsInvoice']['entered_value']; ?></td>
</tr>
    <?php endforeach; ?>



            </table>
            <br><br>