This class comes in both PHP 4 and 5 flavors, but I highly recommend the PHP 5 version, due to the “__destruct()” function that became available in version 5. This helps ensure that you do not inadvertently create memory leaks by forgetting to call the “destruct()” function explicitly, like you must in the PHP 4 version of this script.

If you're using PHP4, are you explicitly calling the destruct method?