CMS pro - Content Management System

Hi! Dear Authors, It’s about CMS pro - Content Management System that I bought from your plateforme there is a few time ago.
My php version is php7.3.7.
I launched CMS pro - Content Management System on my localhost following deeply installation document . But something is wrong when i launch the website that’s :

Warning: Creating default object from empty value in /Applications/MAMP/htdocs/christelle/lib/front.class.php on line 36

Warning: Creating default object from empty value in /Applications/MAMP/htdocs/christelle/index.php on line 248

Fatal error: Uncaught Error: Call to undefined method stdClass::render() in /Applications/MAMP/htdocs/christelle/index.php:251 Stack trace: #0 /Applications/MAMP/htdocs/christelle/lib/router.class.php(256): {closure}() #1 /Applications/MAMP/htdocs/christelle/index.php(252): Router->run(Object(Closure)) #2 {main} thrown in /Applications/MAMP/htdocs/christelle/index.php on line 251.

Please i deeply need your help ,
Thanks.