Wurm client error

Exception

JNLPSigningException[Convalida della firma del file di avvio non riuscita. La versione firmata non corrisponde alla versione scaricata.]
	at com.sun.javaws.jnl.LaunchDesc.checkSigning(Unknown Source)
	at com.sun.javaws.LaunchDownload.checkSignedLaunchDescHelper(Unknown Source)
	at com.sun.javaws.LaunchDownload.checkSignedLaunchDesc(Unknown Source)
	at com.sun.javaws.Launcher.prepareResources(Unknown Source)
	at com.sun.javaws.Launcher.prepareAllResources(Unknown Source)
	at com.sun.javaws.Launcher.prepareToLaunch(Unknown Source)
	at com.sun.javaws.Launcher.prepareToLaunch(Unknown Source)
	at com.sun.javaws.Launcher.launch(Unknown Source)
	at com.sun.javaws.Main.launchApp(Unknown Source)
	at com.sun.javaws.Main.continueInSecureThread(Unknown Source)
	at com.sun.javaws.Main$1.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

Startup

<?xml version="1.0" encoding="utf-8"?>
<jnlp spec="1.0" codebase="http://www.wurmonline.com/client/" href="wurmclient.jnlp">

    <information>
        <title>Wurm Online 3.1.67b</title>
        <vendor>Code Club AB</vendor>
        <homepage href="http://www.wurmonline.com/" />
        <description>Wurm Online client</description>
        <icon href="wurm-icon-128-w.jpg" width="128" height="128" />
        <icon href="wurm-icon-64-w.jpg" width="64" height="64" />
        <icon href="wurm-icon-32-w.jpg" width="32" height="32" />
        <icon href="wurm-icon-16-w.jpg" width="16" height="16" />
        <icon kind="splash" href="splash.gif" />
    </information>

	<shortcut online="true">
		<desktop />
	</shortcut>

	<!-- These are default values, but just to be clear -->
	<update check="timeout" policy="always" />

    <security>
        <all-permissions />
    </security>

    <resources>
        <!-- Java 1.5 is not supported starting from WurmClient 3.1 -->
        <j2se
            href="http://java.sun.com/products/autodl/j2se"
            version="1.6+"
            initial-heap-size="128M"
            max-heap-size="800M"
        />
        <property name="sun.java2d.noddraw" value="true" />
        <property name="org.lwjgl.input.Mouse.allowNegativeMouseCoords" value="true" />
        <jar href="wurmclient.jar" main="true" />
        <jar href="wurmres.jar" />
        <jar href="libraries-stable-2011/colladabind.jar" version="1.0.0" />
        <jar href="libraries-stable-2011/eigcc_java.jar" version="2.0.1" />
        <jar href="libraries-stable-2011/irclib.jar" version="1.10" />
        <jar href="libraries-stable-2011/jogg.jar" version="0.0.7" />
        <jar href="libraries-stable-2011/jorbis.jar" version="0.0.15" />
        <jar href="libraries-stable-2011/joXSI.jar" version="1.0.0" />
        <jar href="libraries-stable-2011/jzipupdate.jar" version="0.9.1" />
        <jar href="libraries-stable-2011/lwjgl.jar" version="2.8.3" />
        <jar href="libraries-stable-2011/lwjgl_util.jar" version="2.8.3" />
        <jar href="libraries-stable-2011/PNGDecoder.jar" version="0.0.1" />
        <jar href="libraries-stable-2011/slick-util.jar" version="b208" />
        <jar href="libraries-stable-2011/vecmath.jar" version="1.5.2" />
    </resources>

    <resources os="Win" arch="x86"><!-- Windows 32-bit java -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-windows.jar" version="2.8.3"/>
        <nativelib href="libraries-stable-2011/eigcc_natives.jar" version="2.0.1"/>
    </resources>
    <resources os="Win" arch="amd64"><!-- Windows 64-bit java -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-windows.jar" version="2.8.3"/>
        <nativelib href="libraries-stable-2011/eigcc_natives.jar" version="2.0.1"/>
    </resources>

    <resources os="Mac" arch="ppc"><!-- PowerPC Mac -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-macosx.jar" version="2.8.3"/>
    </resources>
    <resources os="Mac" arch="i386"><!-- Intel Mac 32-bit java -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-macosx.jar" version="2.8.3"/>
    </resources>
    <resources os="Mac" arch="x86_64"><!-- Intel Mac 64-bit java -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-macosx.jar" version="2.8.3"/>
    </resources>

    <resources os="Linux" arch="i386"><!-- Linux 32-bit Sun java -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-linux.jar" version="2.8.3"/>
    </resources>
    <resources os="Linux" arch="x86"><!-- UNKNOWN -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-linux.jar" version="2.8.3"/>
    </resources>
    <resources os="Linux" arch="amd64"><!-- Linux 64-bit Sun java -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-linux.jar" version="2.8.3"/>
    </resources>
    <resources os="Linux" arch="x86_64"><!-- UNKNOWN -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-linux.jar" version="2.8.3"/>
    </resources>

    <resources os="SunOS" arch="sparc"><!-- UNKNOWN -->
        <nativelib href="libraries-stable-2011/lwjgl-natives-solaris.jar" version="2.8.3"/>
    </resources>

	<application-desc main-class="com.wurmonline.client.WurmLauncher">
    	<argument>jenn001.game.wurmonline.com</argument> 
    </application-desc>
</jnlp>