Magento – move the block of compare products from right to footer page

I had the same error in edit.php file

inside _construct() function

check your block name

$this->_blockGroup = 'your block group here';

hope this will work

Note:

$this->_blockGroup 

should hold block alias name that you set through config.xml.

I think you are missing the file Mymodule/Wine/Block/Adminhtml/Wine/Edit/Form.php
This should be its content:

<?php 
class Mymodule_Wine_Block_Adminhtml_Wine_Edit_Form extends Mage_Adminhtml_Block_Widget_Form
{
    protected function _prepareForm()
    {
        $form = new Varien_Data_Form(
            array(
                'id'         => 'edit_form',
                'action'     => $this->getUrl(
                    '*/*/save',
                    array(
                        'id' => $this->getRequest()->getParam('id')
                    )
                ),
                'method'     => 'post',
                'enctype'    => 'multipart/form-data' //add this only if you have file uploads
            )
        );
        $form->setUseContainer(true);
        $this->setForm($form);
        return parent::_prepareForm();
    }
}