In your removal of Stock By Attributes you did not remove at least the define for the products_with_attributes_stock table which means you have files still on your system.
Besides revisiting your previous install of SBA to identify all of the files that should be removed or restored, to move forward with EP4 you would want to goto tools->developers toolkit, then search for: TABLE_PRODUCTS_WITH_ATTRIBUTES_STOCK then should find it in at least two locations one in the admin/includes/functions/extra_functions file and the other where it looks something like:
Code:
define('TABLE_PRODUCTS_WITH_ATTRIBUTES_STOCK', 'products_with_attributes_stock');