JDS,

To change file permissions, you could either:

1) logon to your domain host account, open their control panel for your domain, go to their file manager program, click on the .htaccess file in the googlecheckout directory, then click the change permissions button.

OR

2) logon to your domain with your FTP program. Depending upon the software, you can usually right click on a file or directory change it. In my old FTP program, when I right click a file, a bunch of option appear including the "CHMOD" command. 777 permissions means the "owner" "group" and "other" categories have all boxes checked for "read" "write" and "execute." Don't forget to switch the .htaccess back to 644 (owner can read and write, everyone else is read only) after you run the htaccess.php file and have confirmed the Google is successfully logging into your zen-cart with the orders.