Error while starting a demo

[wise-coders]

First, congratulations for this project. I want to use it, but I got into issues.

If I run 'gradlew build' I get:
Execution failed for task ':licenseDemo'.

License violations were found

I installed the project under Intellij.
I did 'gradlew idea', next I right-click a demo class, but I receive:
Unable to load class groovyx.javafx.extension.NumberExtension due to missing dependency javafx/beans/value/ObservableNumberValue

What could be wrong?