Why did you ask this question twice? http://splunk-base.splunk.com/answers/33526/what-is-this-backfilling-script
Not sure if you've read the docs on it: http://docs.splunk.com/Documentation/WebIntel/1.0Beta/User/Backfillingdata. "Once setting up the app is complete, you might need to backfill your historical data to view events older than the last five minutes. The Web Intelligence app include data summarizations for 5 minute, hourly, and daily time ranges."