Your issue may have something to with used_in_forms keys didn't get deleted.

Mage::getSingleton('eav/config')
    ->getAttribute('customer', 'demande')
    ->setData('used_in_forms', array('adminhtml_customer', 'customer_account_create', 'customer_account_edit', 'checkout_register'))
    ->save();

Take a look at database table customer_form_attribute and compare it with a older backup

To remove attribute the correct way

/* @var $installer Mage_Eav_Model_Entity_Setup */
$installer->startSetup();\
// Remove Product Attribute
$installer->removeAttribute('customer', 'product_attribute_code');

To fix your issue see Call to a member function getBackend() on a non-object

Your issue may have something to with used_in_forms keys didn't get deleted.

Mage::getSingleton('eav/config')
    ->getAttribute('customer', 'demande')
    ->setData('used_in_forms', array('adminhtml_customer', 'customer_account_create', 'customer_account_edit', 'checkout_register'))
    ->save();

Take a look at database table customer_form_attribute and compare it with a older backup

To remove attribute the correct way

/* @var $installer Mage_Eav_Model_Entity_Setup */
$installer->startSetup();\
// Remove Product Attribute
$installer->removeAttribute('customer', 'product_attribute_code');

To fix your issue see Call to a member function getBackend() on a non-object

To remove attribute the correct way

/* @var $installer Mage_Eav_Model_Entity_Setup */
$installer->startSetup();\
// Remove Product Attribute
$installer->removeAttribute('customer', 'product_attribute_code');

To fix your issue see Call to a member function getBackend() on a non-object

Your issue may have something to with used_in_forms keys didn't get deleted.

Mage::getSingleton('eav/config')
    ->getAttribute('customer', 'demande')
    ->setData('used_in_forms', array('adminhtml_customer', 'customer_account_create', 'customer_account_edit', 'checkout_register'))
    ->save();

Take a look at database table customer_form_attribute and compare it with a older backup

To remove attribute the correct way

/* @var $installer Mage_Eav_Model_Entity_Setup */
$installer->startSetup();\
// Remove Product Attribute
$installer->removeAttribute('customer', 'product_attribute_code');

To fix your issue see Call to a member function getBackend() on a non-object