Probleme applications JAVA / FireFox 3.5

Bonjour,
Probleme JAVA avec FIREFOX 3.5 : je n'arrive pas à ouvrir les jeux java de yahoo : alchemy par exemple !?
j'ai la derniere version de java , le module java est activé sur firefox , mais a chaque essai , j obtiens le message d'erreur suivant :
Java Plug-in 1.6.0_15
Utilisation de la version JRE 1.6.0_15-b03 Java HotSpot(TM) Client VM
Répertoire d'accueil de l'utilisateur = C:\Documents and Settings\William Macleod
--------------------------------------…
c: effacer la fenêtre de la console
f: finaliser les objets de la file d'attente de finalisation
g: libérer la mémoire
h: afficher ce message d'aide
l: vider la liste des chargeurs de classes
m: imprimer le relevé d'utilisation de la mémoire
o: déclencher la consignation
q: masquer la console
r: recharger la configuration des politiques
s: vider les propriétés système et déploiement
t: vider la liste des threads
v: vider la pile des threads
x: effacer le cache de chargeurs de classes
0-5: fixer le niveau de traçage à <n>
--------------------------------------…


charger : classe y.cnt.0 introuvable.
java.lang.ClassNotFoundException: y.cnt.0
at sun.plugin2.applet.Applet2ClassLoader.fi… Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.lo… Source)
at sun.plugin2.applet.Plugin2Manager.create… Source)
at sun.plugin2.applet.Plugin2Manager$Applet… Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.SocketException: Permission denied: connect
at java.net.PlainSocketImpl.socketConnect(N… Method)
at java.net.PlainSocketImpl.doConnect(Unkno… Source)
at java.net.PlainSocketImpl.connectToAddres… Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(U… Source)
at sun.net.www.http.HttpClient.openServer(U… Source)
at sun.net.www.http.HttpClient.<init>(Unkno… Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at java.net.HttpURLConnection.getResponseCo… Source)
at sun.plugin2.applet.Applet2ClassLoader.ge… Source)
at sun.plugin2.applet.Applet2ClassLoader.ac… Source)
at sun.plugin2.applet.Applet2ClassLoader$1.… Source)
at java.security.AccessController.doPrivile… Method)
... 7 more
Exception : java.lang.ClassNotFoundException: y.cnt.0
charger : classe alchemy.Alchemy.class introuvable.
java.lang.ClassNotFoundException: alchemy.Alchemy.class
at sun.plugin2.applet.Applet2ClassLoader.fi… Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.lo… Source)
at sun.plugin2.applet.Plugin2Manager.create… Source)
at sun.plugin2.applet.Plugin2Manager$Applet… Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.SocketException: Permission denied: connect
at java.net.PlainSocketImpl.socketConnect(N… Method)
at java.net.PlainSocketImpl.doConnect(Unkno… Source)
at java.net.PlainSocketImpl.connectToAddres… Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(U… Source)
at sun.net.www.http.HttpClient.openServer(U… Source)
at sun.net.www.http.HttpClient.<init>(Unkno… Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at sun.net.www.protocol.http.HttpURLConnect… Source)
at java.net.HttpURLConnection.getResponseCo… Source)
at sun.plugin2.applet.Applet2ClassLoader.ge… Source)
at sun.plugin2.applet.Applet2ClassLoader.ac… Source)
at sun.plugin2.applet.Applet2ClassLoader$1.… Source)
at java.security.AccessController.doPrivile… Method)
... 7 more
Exception : java.lang.ClassNotFoundException: alchemy.Alchemy.class