We have updated YAGA to work as a plugin for 3.2 and above and it's available here:
I have the same problem. When I click the enable switch it disables as soon as I refresh. When I try to go into Yaga settings it says "Page not found." I tried the change to the config.php file to no avail.
You have to install this version https://vanillaskins.com/plugins.html#yaga in plugins directory.
before, delete the old yaga installation in applications directory.
delete all files in cache directory except .htacess