I attached one file that I know works here:
query_factory.zip

Upload this one to includes/classes/db/mysql/

This overwrites the core file.

Let me know if you still get the error after this,

Regards,

Shaun


NOTE:
With v1.3.9 you don't have to touch the query_factory.php file.
You should use this method instead: http://www.zen-cart.com/forum/showthread.php?t=153582