XML : javafx (ant) build error: Connot find symbol: Alert alert = new Alert(AlertType.Error);

I'm new in javafx. I try to build my procect, where i'll show a Alert but the build faile and show following:

In my ide (eclipse) it's work very well. But if I try to build this project it will faile :((

Techniqual information:
JDK: 1.8.0_66 And my standard library in eclipse is setup to jdk

Thank you in advance