JavaFX 2.0 WebView hangs if the Application is signed

Question

I am using WebView to provide a set of Help pages in my application.
The help pages are included in a resource directory called html.
I get the first URL with the following lines of code:
URL index = NgpConfiguratorApp.class.getResource("/html/index.html");
String url = "file://" + index.getPath();
I then open the URL with WebView and it works perfectly.
I am able to browse my help pages perfectly.
However if I sign the Jar (From within NetBeans using the 6 month valid signature) and then run the program everything works perfectly (XML import/export databse access etc) until I try to access the Help pages through WebView at which pointh the program completely hangs up.
Is this a bug in WebView or am I missing something. I have included the complete class listing below.
COMPLETE LISTING
============
public class HelpBrowser extends Stage {
public HelpBrowser() {
super();
init();
private void init() {
Stage primaryStage = new Stage();
primaryStage.setTitle("AviatorCalc Help Pages");
URL index = NgpConfiguratorApp.class.getResource("/html/index.html");
String url = "file://" + index.getPath();
Group root = new Group();
primaryStage.setScene(new Scene(root));
WebView view = new WebView();
view.setMinSize(1024, 768);
view.setPrefSize(1024, 768);
final WebEngine eng = view.getEngine();
eng.load(url);
final TextField locationField = new TextField(url);
locationField.setMaxHeight(Double.MAX_VALUE);
Button goButton = new Button("Go");
Button backButton = new Button("Back");
goButton.setDefaultButton(true);
goButton.setId("browserbutton");
EventHandler<ActionEvent> goAction = new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
eng.load(locationField.getText().startsWith("") ? locationField.getText()
: "" + locationField.getText());
goButton.setOnAction(goAction);
locationField.setOnAction(goAction);
eng.locationProperty().addListener(new ChangeListener<String>() {
@Override
public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
locationField.setText(newValue);
GridPane grid = new GridPane();
grid.setVgap(5);
grid.setHgap(5);
GridPane.setConstraints(locationField, 0, 0, 1, 1, HPos.CENTER, VPos.CENTER, Priority.ALWAYS, Priority.SOMETIMES);
GridPane.setConstraints(goButton, 1, 0);
GridPane.setConstraints(goButton, 2, 0);
GridPane.setConstraints(view, 0, 1, 2, 1, HPos.LEFT, VPos.CENTER, Priority.ALWAYS, Priority.ALWAYS);
grid.getColumnConstraints().addAll(
new ColumnConstraints(500, 100, Double.MAX_VALUE, Priority.ALWAYS, HPos.CENTER, true),
new ColumnConstraints(40, 40, 40, Priority.NEVER, HPos.CENTER, true));
grid.getChildren().addAll(locationField, goButton, view);
//grid.getChildren().addAll( view);
root.getChildren().add(grid);
primaryStage.show();
}

Answer 1

Many thanks for your prompt replies.
Peterz as per your suggestion I changed the two incorrect lines to:
String url = getClass().getResource("/html/index.html").toExternalForm();
engi.load(url);
It now works perfectly either running as a signed jar or from within the netbeans development system.
The URL that the above creates now looks like this:
"jar:file:/E:/Development/Wireless/netbeans/NgpConfigurator/dist/NgpConfigurator.jar!/html/index.html"
(My development system is on drive E: and my project is called NgpConfigurator).
I am extremely grateful for your help and I hope to contribute to this forum as my experience with JavaFX grows.
Bob Rathbone