You can disable the landscape orienation for screen of Blackberry WebWorks application by adding in config.xml.
Also you need to add
int directions = net.rim.device.api.system.Display.DIRECTION_NORTH;
net.rim.device.api.ui.Ui.getUiEngineInstance().setAcceptableDirections(directions);
after
public Widget( WidgetConfig wConfig, String locationURI ) {
_wConfig = wConfig;
initialize();
_locationURI = locationURI;
in Widget.java which is generally located at C:\Program Files\Research In Motion\BlackBerry WebWorks Packager\device_templates\blackberry\web\widget directory.