jTimer

I've got the following error :

25 oct. 2011 10:24:21 org.jdesktop.application.Task failed
GRAVE: org.chorem.jtimer.ui.tasks.RunTaskJob@683c9314 failed: java.lang.UnsatisfiedLinkError: Unable to load library 'Xss': libXss.so: Ne peut ouvrir le fichier d'objet partagé: Aucun fichier ou dossier de ce type
java.lang.UnsatisfiedLinkError: Unable to load library 'Xss': libXss.so: Ne peut ouvrir le fichier d'objet partagé: Aucun fichier ou dossier de ce type
    at com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:164)
    at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:237)
    at com.sun.jna.Library$Handler.<init>(Library.java:140)
    at com.sun.jna.Native.loadLibrary(Native.java:375)
    at com.sun.jna.Native.loadLibrary(Native.java:360)
    at org.chorem.jtimer.ui.system.unix.Xss.<clinit>(Xss.java:41)
    at org.chorem.jtimer.ui.system.unix.UnixSystemInfo.getXssIdleTime(UnixSystemInfo.java:95)
    at org.chorem.jtimer.ui.system.unix.UnixSystemInfo.getIdleTime(UnixSystemInfo.java:63)
    at org.chorem.jtimer.ui.tasks.RunTaskJob.doInBackground(RunTaskJob.java:269)
    at org.chorem.jtimer.ui.tasks.RunTaskJob.doInBackground(RunTaskJob.java:56)
    at org.jdesktop.swingworker.SwingWorker$1.call(Unknown Source)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at org.jdesktop.swingworker.SwingWorker.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)