How to use JavaFXPorts

Now,I get started to using JavaFXPorts and I’d like to create a Application that is capable of
running in android.I tried to create it but I encountered some errors.

I installed follwing procdure:
(1)Eliminate artifacts.xml.
[My Path]
If I didn’t eliminate artifacts.xml, I can’t properly install “Gradle Integration for Eclipse”.

(2)Install “Gradle Integration for Eclipse”
I refered to the following URL(Chapter:Update Site):

(3)Create “Basic Gradle Application”
I refered to the above URL(Chapter:Creating a new Gluon Project)

then,I encountered errors like the attached picture.
Please let me know how to resolve the errors.
enter image description here