How about instead ... get the download of Zen Cart v1.3.7 from the Download at the top of your screen ...

Load all files to your site ...

Get the current PayPal Patch at:
http://www.zen-cart.com/forum/showthread.php?t=56216

Load that to your site too and update your clean v1.3.7 Zen Cart that you just downloaded with those new files ...

Then drop your database table (assuming this has nothing of value in it) ... and reinstall it again ...

NOTE: if using the same directory to install to, you should overwrite the two configure.php files with either empty files or dist-configure.php so that you can do a fresh install the right way ...