Error while compiling Writing Gradle Plugin tutorial

I am working on IntelliJ, JDK9 following the tutorial on the site about Writing Gradle Plugins (https://guides.gradle.org/writing-gradle-plugins/?_ga=2.189939243.1251448586.1531732864-325483170.1529678856)

When I try to compile the build and configure build carshes and I the get error message:

Could not get unknown property ‘org’ for root project ‘greeting-plugin’ of type org.gradle.api.Project.
Open File

I realized that it has to do with the apply plugin: org.example.greeting.GreetingPlugin I am using in the build.gradle file in the main directory.

Does anyone have an idea how to fix this?:ghost: