#2 prototypeWTP not installable

[Anonymous]

On internet I found a approach to install prototypeWTP:

step1:download prototypeWTP(version)forPrototype(version).jar
step2:find you Eclipse Plugin org.eclipse.wst.javascript.ui_xxxxxxx.jar,backup the plugin.
step3:double click the jar file or run with command java -jar prototypeWTP(version)forPrototype(version).jar
step4:on the opened swing UI,choose org.eclipse.wst.javascript.ui_xxxxxxx.jar,and output dir.
step5:click generate button.
step6:replace old org.eclipse.wst.javascript.ui_xxxxxxx.jar file with the generated file.
step7:restart eclipse.
step8:open a html file,edit js content.

However step 3 results in:
D:\Desktop>java -jar prototypeWTP0.2forPrototype1.6.0.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad version number in .class file
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)

Help please??