If you still see the Juicebox logo in the lower right corner, then the gallery is still Juicebox-Lite.
The Juicebox logo is present in all Lite galleries but not in any Pro galleries.

First of all, please try completely clearing your browser's cache before reloading your gallery's web page to see if the problem is a browser caching issue. (Your browser might be storing and using the Lite files.)

If this does not clear the problem, then please try the Upgrading to Juicebox-Pro instructions again but, this time, try deleting the Lite 'jbcore' folder from your web server first before uploading the Pro version in its place.

Please note that upgrading WP-Juicebox to Juicebox-Pro does not change the plugin's interface.
Only Lite options will have their own individual controls but all Pro options entered in the Pro Options text area will become active.

I hope this helps.