when invoking jemplode I receive the following error(s)

> java -jar jemplode20.jar

java.lang.ClassFormatError: Unknown constant tag in .class file
at sun.awt.image.InputStreamImageSource.addConsumer(InputStreamImageSource.java:86)
at sun.awt.image.InputStreamImageSource.startProduction(InputStreamImageSource.java:149)
at sun.awt.image.ImageRepresentation.startProduction(ImageRepresentation.java:634)
at sun.awt.image.ImageRepresentation.prepare(ImageRepresentation.java:672)
at sun.awt.motif.MToolkit.prepareScrImage(MToolkit.java:270)
at sun.awt.motif.MToolkit.prepareImage(MToolkit.java:294)
at java.awt.Component.prepareImage(Component.java:2327)
at java.awt.ImageMediaEntry.startLoad(MediaTracker.java:887)
at java.awt.MediaEntry.getStatus(MediaTracker.java:837)
at java.awt.ImageMediaEntry.getStatus(MediaTracker.java:883)
at java.awt.MediaTracker.statusID(MediaTracker.java:670)
at java.awt.MediaTracker.waitForID(MediaTracker.java:618)
at java.awt.MediaTracker.waitForID(MediaTracker.java:587)
at org.jempeg.empeg.emplode.ImageCanvas.setImage(ImageCanvas.java:69)
at org.jempeg.empeg.emplode.ImageCanvas.<init>(ImageCanvas.java:58)
at org.jempeg.empeg.emplode.Splash.createWindow(Splash.java:85)
at org.jempeg.empeg.emplode.Splash.show(Splash.java:96)
at org.jempeg.empeg.emplode.Main.main(Main.java:55)
Exception in thread "main" java.lang.ClassFormatError: Unknown constant tag in .class file
at sun.awt.image.InputStreamImageSource.addConsumer(InputStreamImageSource.java:86)
at sun.awt.image.InputStreamImageSource.startProduction(InputStreamImageSource.java:149)
at sun.awt.image.ImageRepresentation.startProduction(ImageRepresentation.java:634)
at sun.awt.image.ImageRepresentation.prepare(ImageRepresentation.java:672)
at sun.awt.motif.MToolkit.prepareScrImage(MToolkit.java:270)
at sun.awt.motif.MToolkit.prepareImage(MToolkit.java:294)
at java.awt.Component.prepareImage(Component.java:2327)
at java.awt.ImageMediaEntry.startLoad(MediaTracker.java:887)
at java.awt.MediaEntry.getStatus(MediaTracker.java:837)
at java.awt.ImageMediaEntry.getStatus(MediaTracker.java:883)
at java.awt.MediaTracker.statusID(MediaTracker.java:670)
at java.awt.MediaTracker.waitForID(MediaTracker.java:618)
at javax.swing.ImageIcon.loadImage(ImageIcon.java:226)
at javax.swing.ImageIcon.<init>(ImageIcon.java:121)
at javax.swing.ImageIcon.<init>(ImageIcon.java:134)
at org.jempeg.empeg.emplode.plaf.PlaylistTreeCellRenderer.<clinit>(PlaylistTreeCellRenderer.java:58)
at org.jempeg.empeg.emplode.Emplode.initGUI(Emplode.java:431)
at org.jempeg.empeg.emplode.Emplode.<init>(Emplode.java:169)
at org.jempeg.empeg.emplode.Main.main(Main.java:82)

I've tried restarting my X session, with no improvement. Any suggestions appreciated.

Thanks,

Michael