Changed configuration output directory to: GOOGLE_PRODUCTS_DIRECTORY
GOOGLE_PRODUCTS_DIRECTORY is simply a directive in the googlefroogle.php file that tells the feed to load the file in the folder selected in the configuration. It is not a directory itself.

Warning: opendir(/home/herbschi/public_html/zen/GOOGLE_PRODUCTS_DIRECTORY) [function.opendir]: failed to open dir: No such file or directory in /home/herbschi/public_html/zen/xxxxxxx/googlefroogle.php on line 185
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What this message means is that the directive was unable to execute because it could not find the folder. This would happen because either a) The folder doesn't exist, b) The folder name doesn't match the name in the configuration, or c) The folder permissions are wrong.

Set the folder name in the configuration to feed/. Then make sure a folder named feed is in the root of your store - zen/feed. Then make sure the permissions are set correctly, try either 755 or 777.