ical 6 wont import from 5.0.3

Have just bought a new Mac Mini running 10.8 and ical 6. Did a migration from the old mac to new and everything works fine except in iCal it wont import any calendars that were created on my older macs 10.7.4 running iCal 5.0.3. These are hosted on a server and not icloud. I have tried deleating them in 6 and reimporting them to no avail. Can get them in through putting address into web browser but this does not update/refresh. Have contacted apple and they are looking into it - any sugestions?