Just checked the plugins. The incompatibility seems to be with WP Pipes. When I deactivate it, I can activate this one. But then, this other gives me a very similar error:
Fatal error: Cannot redeclare class Controller in C:\xampp\htdocs\wordpress\wp-content\plugins\wp-pipes\includes\controller.php on line 11
Seems that both tryies to define the same class ‘Controller’?
