It seems Facebook keeps making things more and more difficult on Pages, and you'll notice another change today.

Once your Event has been created, you can no longer just add guests from the main Event page. In order to do so, follow these simple instructions...

1. Click on the Event you want to invite people to
2. Click the little arrow pointing down with the the gear in the very top right corner (there will be a drop down menu)
3. Select 'edit event'
4. Then look for 'Who's Invited' and 'Select more guests'

From here, you will be able to sort your friends by friend lists and groups. Check the box next to your friends' names and click 'Submit' to send them an invitation to your event.

Hope this helps!!