osmosis error, class not found

Hey everybody,

i have a big problem with osmosis. I had followed the manual at http://wiki.openstreetmap.org/wiki/Osmosis/Installation but i get the following:


Exception in thread "main" java.lang.NoClassDefFoundError: org/openstreetmap/osmosis/core/Osmosis
Caused by: java.lang.ClassNotFoundException: org.openstreetmap.osmosis.core.Osmosis
    at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
    at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
Could not find the main class: org.openstreetmap.osmosis.core.Osmosis.  Program will exit.

i have installed java 1.6 and all other required programms.

What is going wrong.

OS: Ubuntu 10.09
Java: java version “1.6.0_15”, Java™ SE Runtime Environment (build 1.6.0_15-b03), Java HotSpot™ Client VM (build 14.1-b02, mixed mode, sharing)