Good evening Tasha and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the 404 errors you are experiencing following the installation of Event Tickets Plus 4.4.5. Yikes!
I would love to help you with this topic.
The first thing I would try would be to go to Events -> Settings -> General and change the slug for Single event URL slug to AND flushing your permalinks.
If that does not work, I would take a look at your WP engine caching to make sure it is not interfering.
Another solution (with a backup) would be to downgrade to WooCommerce 2.6.14.
Let me know how that goes.
Have a good weekend,
Geoff B.