I’m not exactly sure what issue you’re experiencing as the link you’ve shared doesn’t work – however, it sounds like you have a communication breakdown between your site and Eventbrite.
Check out our New User Primer: Eventbrite Tickets Knowledgebase article; it may help solve the error you’re seeing. Keep me informed on the status of your issue and thanks for choosing PRO!
We are unfortunately unable to log into your account for any reason, so please refrain from sending over credentials. And just to clear up any confusion – 1) are you having trouble installing and activating the plugin or 2) are you having trouble once the plugin has been installed and activated?
Additionally, would you mind sending over your System Information as a private reply? This may help expedite the process.