Message d erreur dans l application java

Bonjour a tous ,

j ai un soucis, suite a une reinstalation systeme, je n arrive plus a me conecter sur les certains sites de chat
lorsque je lance un message d erreur echec dans l aplication sur la page de lancement java
et sur le dedail voici c qui il y ...
Exception in thread "CacheCleanUpThread" java.lang.NullPointerException
at com.sun.deploy.cache.CleanupThread.getCurrentCacheSize(Unknown Source)
at com.sun.deploy.cache.CleanupThread.run(Unknown Source)
charger : classe chatland.EIRC.class introuvable.
java.lang.ClassNotFoundException: chatland.EIRC.class
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.io.IOException: open HTTP connection failed:http://irc5.chat-land.org/jar/chatland/EIRC/class.class
at sun.plugin2.applet.Applet2ClassLoader.getBytes(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader.access$000(Unknown Source)
at sun.plugin2.applet.Applet2ClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
... 7 more
Exception : java.lang.ClassNotFoundException: chatland.EIRC.class
merci de m aidé a resoudre mon soucis je suis nul en informatique lol
a bientot