I have been troubleshooting this error for the past few days - and have hit a brick wall. I am running NetBeans v11.3, and Ubuntu Bionic (v18.04.4).
I have installed Java versions 8 and 11 (openjdk) along with source code.
I have also installed javaFx versions 8 and 11 with source code.
I have even gone to "Tools -> Java Platform Manager" and ensured that v8 and v11 of Java are properly installed along with the appropriate "Platform Sources".
But I still get the error mentioned when I try to create a new JavaFX project.
Any help would be very much appreciated.NetBeans JavaFX project create error