com.wuala.platform.Wuala not found

I get the error message below ... application used to work fine for over 6 months if not longer ... now it won't start.

Wuala closed because of an unexpected error.
If you want us to know about this problem, please send this text to bug_high_prio@wua.la,
or discuss it on http://forum.wua.la .

Date: Fri Oct 24 21:21:46 CEST 2008
OS: Windows Vista 1.6.0_10-rc Sun Microsystems Inc.
Memory: 266403840 max 49083896 free 52035584 total
Local Host: Insp9400/85.222.81.146
Loader version: 2 (July 18, 2008)

java.lang.ClassNotFoundException: com.wuala.platform.Wuala not found
at com.wuala.loader2.starter.WualaClassLoader.findWualaClass(WualaClassLoader.java:56)
at com.wuala.loader2.starter.WualaClassLoader.loadClass(WualaClassLoader.java:35)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.wuala.loader2.Loader2.startInstance(Loader2.java:57)
at com.wuala.loader2.Loader2.start(Loader2.java:44)
at com.wuala.loader2.Loader2.main(Loader2.java:106)
Caused by: java.io.IOException: com/wuala/platform/Wuala.class not found
at com.wuala.loader2.loader.data.AbstractLocalCompilation.get(AbstractLocalCompilation.java:48)
at com.wuala.loader2.starter.WualaClassLoader.findWualaClass(WualaClassLoader.java:43)
... 5 more

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java.io.IOException: com/wuala/platform/Wuala.class not found
at com.wuala.loader2.loader.data.AbstractLocalCompilation.get(AbstractLocalCompilation.java:48)
at com.wuala.loader2.starter.WualaClassLoader.findWualaClass(WualaClassLoader.java:43)
at com.wuala.loader2.starter.WualaClassLoader.loadClass(WualaClassLoader.java:35)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.wuala.loader2.Loader2.startInstance(Loader2.java:57)
at com.wuala.loader2.Loader2.start(Loader2.java:44)
at com.wuala.loader2.Loader2.main(Loader2.java:106)