So my first thought was that this addon is simply outdated and maybe that above code is no longer valid. I believe this is not the case though as I can find nothing wrong with that code, and have tried other versions of it. After trying many things I decided to instead copy the current site and instead upgrade it to the current version via shell following the instructions here:
So this is very interesting as I am now getting the same error I was with the fresh install of Magento where I was trying to install an addon. But this one is basically showing that the core Magento scripts that are trying to update the database is having the same problems with the code when it runs. It seems like anything that tries to retreive the entity config customer/eav_attribute has problems.
The difficult part with this is that for a fresh install of Magento this problem happens, and then for and upgrade to an old site with an old database this happens when Magento goes through the upgrade process.
For reference I have tried a few things from what I have found elsewhere including:
UPDATE `eav_entity_type` SET `attribute_model` = 'customer/attribute', `additional_attribute_table` = 'customer/eav_attribute', `entity_attribute_collection` = 'customer/attribute_collection' WHERE `eav_entity_type`.`entity_type_code` = 'customer';
but that has no effect since the values in the table in the database are already set to what this was doing. So that fix does not work. Someone else mentioned that adding an order_by field as a varchar(2) to the customer_eav_attribute table might fix the problem. This did not work either.