I am getting runtime error while running a JavaFX application developed using IDE Netbeans on Linux (OpenSuse 12.1).

The "Hello World" application is built without any error. However, if I run (from Netbeans), it gives me an output which only shows the frame (stage in JavaFX term ?), no buttons, as attached (HelloWorld.jpg).

It throws the following error:
[code]
compile:
Detected JavaFX Ant API version 1.1
Launching <fx:jar> task from /usr/lib/jvm/javafx-sdk2.1.0/lib/ant-javafx.jar
Launching <fx:deploy> task from /usr/lib/jvm/javafx-sdk2.1.0/lib/ant-javafx.jar
Skip jar copy to itself: MyJavaFX.jar
jfx-deployment:
jar:
run:
SEVERE: javafx.scene.control.Control loadSkinClass Failed to load skin 'StringProperty [bean: Button[id=null, styleClass=button], name: skinClassName, value: com.sun.javafx.scene.control.skin.ButtonSkin]' for control Button[id=null, styleClass=button]
java.lang.NullPointerException
   at com.sun.javafx.font.FontConfigManager.populateMapsNative(Native Method)
   at com.sun.javafx.font.FontConfigManager.populateMaps(FontConfigManager.java:228)
   at com.sun.t2k.T2KFontFactory.getFullNameToFileMap(T2KFontFactory.java:1407)
   at com.sun.t2k.T2KFontFactory.getFontResource(T2KFontFactory.java:400)
   at com.sun.t2k.LogicalFont.getSlot0Resource(LogicalFont.java:187)
   at com.sun.t2k.LogicalFont.getSlotResource(LogicalFont.java:228)
   at com.sun.t2k.CompositeStrike.getStrikeSlot(CompositeStrike.java:91)
   at com.sun.t2k.CompositeStrike.getMetrics(CompositeStrike.java:137)
   at com.sun.javafx.font.PrismFontUtils.getFontMetrics(PrismFontUtils.java:31)
   at com.sun.javafx.font.PrismFontLoader.getFontMetrics(PrismFontLoader.java:439)
   at javafx.scene.text.Text.<init>(Text.java:129)
   at com.sun.javafx.scene.control.skin.LabeledText.<init>(LabeledText.java:30)
   at com.sun.javafx.scene.control.skin.LabeledSkinBase.<init>(LabeledSkinBase.java:128)
   at com.sun.javafx.scene.control.skin.ButtonSkin.<init>(ButtonSkin.java:46)
   at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
   at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
   at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
   at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
   at javafx.scene.control.Control.loadSkinClass(Control.java:999)
   at javafx.scene.control.Control.access$500(Control.java:74)
   at javafx.scene.control.Control$12.invalidated(Control.java:918)
   at javafx.beans.property.StringPropertyBase.markInvalid(StringPropertyBase.java:127)
   at javafx.beans.property.StringPropertyBase.set(StringPropertyBase.java:161)
   at com.sun.javafx.css.StyleableStringProperty.set(StyleableStringProperty.java:71)
   at javafx.scene.control.Control$12.set(Control.java:910)
   at com.sun.javafx.css.StyleableStringProperty.applyStyle(StyleableStringProperty.java:59)
   at com.sun.javafx.css.StyleableStringProperty.applyStyle(StyleableStringProperty.java:31)
   at com.sun.javafx.css.StyleableProperty.set(StyleableProperty.java:62)
   at com.sun.javafx.css.StyleHelper.transitionToState(StyleHelper.java:807)
   at javafx.scene.Node.impl_processCSS(Node.java:6476)
   at javafx.scene.Parent.impl_processCSS(Parent.java:1127)
   at javafx.scene.control.Control.impl_processCSS(Control.java:1109)
   at javafx.scene.Parent.impl_processCSS(Parent.java:1134)
   at javafx.scene.Node.processCSS(Node.java:6444)
   at javafx.scene.Scene.doCSSPass(Scene.java:422)
   at javafx.scene.Scene.preferredSize(Scene.java:1210)
   at javafx.scene.Scene.impl_preferredSize(Scene.java:1260)
   at javafx.stage.Window.adjustSize(Window.java:185)
   at javafx.stage.Window.access$1000(Window.java:72)
   at javafx.stage.Window$10.invalidated(Window.java:707)
   at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:129)
   at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:163)
   at javafx.stage.Window.setShowing(Window.java:768)
   at javafx.stage.Window.show(Window.java:783)
   at javafx.stage.Stage.show(Stage.java:207)
   at myjavafx.MyJavaFX.start(MyJavaFX.java:44)
   at com.sun.javafx.application.LauncherImpl$5.run(LauncherImpl.java:315)
   at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:174)
   at com.sun.javafx.application.PlatformImpl$3.run(PlatformImpl.java:141)
   at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
   at com.sun.glass.ui.gtk.GtkApplication$2$1.run(GtkApplication.java:79)
   at java.lang.Thread.run(Thread.java:722)
 
SEVERE: javafx.scene.control.Control impl_processCSS The -fx-skin property has not been defined in CSS for Button[id=null, styleClass=button]
[/code]

The source code is:
[code]
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package myjavafx;
 
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
 
/**
 *
 * @author jrahman
 */
public class MyJavaFX extends Application {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }
    
    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("Hello World!");
        Button btn = new Button();
        btn.setText("Say 'Hello World'");
        btn.setOnAction(new EventHandler<ActionEvent>() {
 
            @Override
            public void handle(ActionEvent event) {
                System.out.println("Hello World!");
            }
        });
        
        StackPane root = new StackPane();
        root.getChildren().add(btn);
        primaryStage.setScene(new Scene(root, 300, 250));
        primaryStage.show();
    }
}
[/code]