GPS Data Logger Software - BT747

Starting bt747 I see following exception from java:

>>>>>>> CAUGHT UNHANDLED EXCEPTION IN SuperWaba EVENT THREAD:
java.lang.NoClassDefFoundError: Could not initialize class gnu.io.CommPortIdentifier
at gps.connection.GPSRxTxPort.openPort(Unknown Source)
at gps.connection.GPSrxtx.myOpenPort(Unknown Source)
at gps.connection.GPSrxtx.openPort(Unknown Source)
at bt747.model.Controller.connectGPS(Unknown Source)
at bt747.waba_view.GPSconctrl.onEvent(Unknown Source)
at waba.ui.Control.postEvent(Control.java:611)
at waba.ui.Button.onEvent(Button.java:203)
at waba.ui.Control.postEvent(Control.java:611)
at waba.ui.Window._postEvent(Window.java:574)
at waba.applet.SWEventThread.handleOneEvent(SWEventThread.java:84)
at waba.applet.SWEventThread.run(SWEventThread.java:48)
at java.lang.Thread.run(Thread.java:745)
30083 - 30083 - Freeport is

Trying run_rxtx.sh gives the same error:

>>>>>>> CAUGHT UNHANDLED EXCEPTION IN SuperWaba EVENT THREAD:
java.lang.NoClassDefFoundError: Could not initialize class gnu.io.CommPortIdentifier
at gps.connection.GPSRxTxPort.openPort(Unknown Source)
at gps.connection.GPSrxtx.myOpenPort(Unknown Source)
at gps.connection.GPSrxtx.openPort(Unknown Source)
at bt747.model.Controller.connectGPS(Unknown Source)
at bt747.waba_view.GPSconctrl.onEvent(Unknown Source)
at waba.ui.Control.postEvent(Control.java:611)
at waba.ui.Button.onEvent(Button.java:203)
at waba.ui.Control.postEvent(Control.java:611)
at waba.ui.Window._postEvent(Window.java:574)
at waba.applet.SWEventThread.handleOneEvent(SWEventThread.java:84)
at waba.applet.SWEventThread.run(SWEventThread.java:48)
at java.lang.Thread.run(Thread.java:745)
30083 - 30083 - Freeport is

The library in question is installed:

root@nc409-muc:/opt/bt747# ll /usr/share/java/RXTXcomm.jar
lrwxrwxrwx 1 root root 20 Jul 26 2014 /usr/share/java/RXTXcomm.jar -> RXTXcomm-2.2pre2.jar
root@nc409-muc:/opt/bt747# ll /usr/share/java/RXTXcomm-2.2pre2.jar
-rw-r--r-- 1 root root 61087 Jul 26 2014 /usr/share/java/RXTXcomm-2.2pre2.jar

Putting the library into the classpath does not help. Same error. The native library used by the jar is installed too:

ii librxtx-java 2.2pre2-13 armhf Full Java CommAPI implementation

Any idea why this library works with other tools, but not with bt747 or rxtx from the same package?