Java SE (Java Platform, Standard Edition)

Hello all,
Iv'e got an application here that sign file with digital signature.
Everything is fine when I run the code locale in my eclipse.
But when I deploy it on my server and execute it with webstart. the method dont work ..
Ive got this error .

java.lang.UnsupportedOperationException
at java.security.cert.CertificateFactorySpi.engineGenerateCertPath(Unknown Source)
at java.security.cert.CertificateFactory.generateCertPath(Unknown Source)
at java.security.cert.CertPath$CertPathRep.readResolve(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at java.io.ObjectStreamClass.invokeReadResolve(Unknown Source)
at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.defaultReadFields(Unknown Source)
at java.io.ObjectInputStream.readSerialData(Unknown Source)
at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.readObject(Unknown Source)
at com.sun.deploy.cache.CacheEntry.readManifest(Unknown Source)
at com.sun.deploy.cache.CacheEntry.readManifest(Unknown Source)
at com.sun.deploy.cache.CacheEntry.getManifest(Unknown Source)
at com.sun.deploy.cache.CachedJarFile.getManifest(Unknown Source)
at sun.misc.URLClassPath$JarLoader$2.getManifest(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$000(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 com.sun.jnlp.JNLPClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)

Did someone know why webstart can't generate the certpath.. Did Web start has some browser dependency that not allowed me to do something like this ?

I realy need help on this !!

Thx
Chris.