Hi, Janet!
Thank you for using The Events Calendar! I can help with this 🙂
I’m sorry to hear about the frustration but I think I can help here.
Event Aggregator is part of The Events Calendar plugin. Once you enter your license in the license tab it will allow you to import without any problems. The error you’re getting leads me to believe you might not have entered your license. Does this sound right?
Let me know if this helps. If not we may have a different bug on our hands!
Cheers,
Trisha