Receiving error message when trying to install Cloner

On my website kakekorner.com, I am trying to install cloner
I get this error message:
Plugin could not be activated because it triggered a fatal error.
Fatal error: Call to undefined function is_subdomain_install() in /home/content/j/p/s/jpskakekorner/html/wp-content/plugins/cloner/integration/integration.php on line 93