If you registered the site when you were browsing to it using the IP, that's what's been registered.
Wait until you get your DNS name figured out, then reset your license while making sure that you're using the domain name to browse to the calendar. That should fix you up.
EPC Tutorials... We're here to help!
Offering custom integration services. Contact me here
* Not affiliated with EasyPHPCalendar or NashTech Inc.