We were getting this exact same error running Zen Cart 1.3.9 without COWOA. A plain vanilla install.
Code:
1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ':email AND COWOA_account != 1' at line 9
line number is irrelevant because fault is much further down.

Find header_php.php somewhere in /includes/modules/pages/login/
Code:
includes/modules/pages/login/header_php.php
First of all make a backup copy of header_php.php by adding an X at end of .php EG (header_php.phpx)

Now edit a copy of header_php.php by looking for
Code:
WHERE customers_email_address = :email
and change :email to :emailAddress
Save and upload, replacing faulty header_php.php

:emailAddress appears a few lines later.

This is repeating an answer from an earlier thread for current users.