cannot run pycharm 2.5.1 on kubuntu inux
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I want to run pycharm 2.5.1 on kubuntu but i get this error

    mohammad@mohammad-Inspiron-1564:/media/storage/Linux/pycharm-2.5.1/bin$ sh pycharm.sh 
    OpenJDK Runtime Environment (IcedTea7 2.1.1pre) (7~u3-2.1.1~pre1-1ubuntu3)
    OpenJDK 64-Bit Server VM (build 22.0-b10, mixed mode)
    OpenJDK 64-Bit Server VM (build 22.0-b10, mixed mode)
    WARNING: You are launching the IDE using OpenJDK Java runtime.
    
             ITS KNOWN TO HAVE PERFORMANCE AND GRAPHICS ISSUES!
             SWITCH TO THE ORACLE(SUN) JDK BEFORE REPORTING PROBLEMS!
    
    NOTE:    If you have both Oracle (Sun) JDK and OpenJDK installed
             please validate either PYCHARM_JDK, JDK_HOME, or JAVA_HOME environment variable points to valid Oracle (Sun) JDK installation.
             See http://ow.ly/6TuKQ for more info on switching default JDK.
    
    Press Enter to continue.
    
    Error occurred during initialization of VM
    java/lang/ClassNotFoundException: error in opening JAR file ../lib/boot.jar

before Kubuntu i have opensuse and ubuntu and I have no problem to run pycharm but i dont know why it occurs

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Regards
Mohammad