Why some features don't work on Magento 1.3.x?
Starting with Magento 1.4 developers had changed the recommended path for storing extension templates.
It was done to avoid some issues on the user's end.
The extension conforms to the new standards, so older Magento versions can't find some of the templates. To fix this problem copy the files from the install_13 folder to the Magento root folder — where your index.php is located.