Gallery - Error EXO

I just purchased the Gallery add-on. I re-download the complete suite to get the "gallery" folder from the "applications" folder. I then uploaded the "gallery" folder into the "applications" folder on my server.

Went to the back end, Installed it, checked permissions, seemed fine, went to the front end, it showed up in navigation bar, but when I click on it, I get the following message:

Sorry, there is a problem
Something went wrong. Please try again.
Error code: EX0

Anyone know how to resolve this issue? Thank you in advance for your help.

UPDATE

Gallery now working. I guess it was not working because I still had "Designers Mode" enabled. Once I disabled it and it synced the theme back, it started working!