You would be better off downloading the current version of Zen Cart ... v1.3.7.1 and doing a manual upgrade of your site by loading the files from the program then running the Upgrade via the:
/zc_install
NOTE: Always backup both your database and your site ... before doing an upgrade ...
You can obtain the current release following this thread:
http://www.zen-cart.com/forum/showthread.php?t=69769
NOTE: if you have a live site it is often better to upgrade a copy of your site first ...
To learn how to do an effective upgrade, a search on:
/new_shop
will locate numerous threads posted over the last year that detail how do to a safe upgrade ...
You'll also find documented upgrade instructions in your /docs folder of your Zen Cart files.