This issue is still not resolved in the latest version 2.3.5 for Smooth Slider. In the meantime, I found a solution!
To activate the Smooth Slider, you can edit the settings.php file in the Smooth Slider settings folder.
Search for the two instances of register_mysettings and rename to register_mysettings_ss
You should be active to activate the plug-in without issues.
What other post? Can you provide a link? Thanks! 🙂