If the auction does not meet the reserve price, will it automatically renew?
When an auction automatically renews does it create another charge to the lister's paypal? Will the charge process without another authorization from the lister?
Make sure you have setup your cron task to expire ads in admin options. I would use a timeframe of 86399 which is once a day to check things.
The cron task in Admin Options is set to a default 1440. Is that ok? Sounds like it runs frequently.