Error when I click on edit customer in the admin panel

Question

Manage Customers throwing customer activation errors:

Source model customeractivation/resource_attribute_source_customeractivation not found for attribute customer_activated

Answer 1

Seems you have used an extension called "customeractivation" (or something similar) and uninstalled it. The customer attribute customer_activated seems to be created through that extension.

If this extension isn't in use anymore, I recommend to remove the attribute.

Create and run this file from your Magento root:

require 'app/Mage.php';
Mage::app('admin');

$setup = Mage::getModel('eav/entity_setup', 'core_setup');
$setup->startSetup();
$setup->removeAttribute('customer', 'customer_activated');
$setup->endSetup();

Answer 2

I think there was a module named customeractivation, which has been uninstalled.

Since the attribute created by module still exists and it is referencing to the source model of the module, the issue is appearing.

If you have access to the database, find out which customer attribute uses that source model:

SELECT attribute_id, attribute_code FROM eav_attribute WHERE source_model='customeractivation/resource_attribute_source_customeractivation';

Then either try to remove it from the admin panel, Customers -> Attributes -> Manage Customer Attributes (if you have any such interface) or directly from the DB after you made sure you have proper backups.