Java SE (Java Platform, Standard Edition)

Hi All,
I'm using JNLPAppletLauncher for applet execution which uses the custom DLL for some operation that is accessed by JNA API.

Here is my HTML

<applet code="org.jdesktop.applet.util.JNLPAppletLauncher"
      width=700
      height=350
      archive="http://www.webstoreshoppingcart.com/applet/lib/CLPApplet.jar,
               http://download.java.net/media/applet-launcher/applet-launcher.jar,
               http://download.java.net/media/java3d/webstart/release/j3d/latest/j3dcore.jar,
               http://download.java.net/media/java3d/webstart/release/j3d/latest/j3dutils.jar,
               http://download.java.net/media/jogl/builds/archive/jsr-231-webstart-current/jogl.jar,
               http://download.java.net/media/gluegen/webstart/gluegen-rt.jar,
               http://download.java.net/media/java3d/webstart/release/vecmath/latest/vecmath.jar">
   <param name="codebase_lookup" value="false">
   <param name="subapplet.classname" value="com.gtpl.applet.CLPApplet">
   <param name="subapplet.displayname" value="My Java 3D Applet">
   <param name="jnlpNumExtensions" value="2">
   <param name="jnlpExtension1" value="http://download.java.net/media/java3d/webstart/release/java3d-latest.jnlp">
   <param name="jnlpExtension2" value="http://www.webstoreshoppingcart.com/applet/clp-appletlauncher.jnlp">
   <param name="progressbar" value="true">
   <param name="noddraw.check" value="true">
 </applet>

My JNLP (clp-appletlauncher.jnlp)

<?xml version="1.0" encoding="UTF-8"?>
<jnlp codebase="http://www.webstoreshoppingcart.com/applet/lib/" spec="1.0+">
	<information>
		<title>CLP 3D</title>
		<vendor>XYZ, Inc.</vendor>
		<homepage href="http://www.mysite.com/"/>
		<description>CLP</description>
		<offline-allowed/>
	</information>
	
	<security>
		<all-permissions/>
	</security>
	
    <resources>
		<jar href="jna.jar"/>		
		<nativelib href="clp-dll.jar"/>		
    </resources>
				
    <component-desc />
</jnlp>

clp-dll.jar contains my 2 dll files, namely "CLP.dll" & "jnidispatch.dll"

My problem is I'm getting the exception saying the CLP.dll file is not certifid.
This is the actual exception:

processNativeJar: using previously cached: C:\Documents and Settings\gtpl201\.jnlp-applet\cache\webstoreshoppingcart_com\e3dd149426f6ef740affa87b27fb5a1a8538faca\clp-dll.jar
validateCertificates:
VALIDATE: CLP.dll
java.io.IOException: Cannot validate certificate for CLP.dll
	at org.jdesktop.applet.util.JNLPAppletLauncher.validateCertificates(JNLPAppletLauncher.java:1815)
	at org.jdesktop.applet.util.JNLPAppletLauncher.processNativeJar(JNLPAppletLauncher.java:1579)
	at org.jdesktop.applet.util.JNLPAppletLauncher.initResources(JNLPAppletLauncher.java:1350)
	at org.jdesktop.applet.util.JNLPAppletLauncher.initAndStartApplet(JNLPAppletLauncher.java:1254)
	at org.jdesktop.applet.util.JNLPAppletLauncher.access$000(JNLPAppletLauncher.java:658)
	at org.jdesktop.applet.util.JNLPAppletLauncher$1.run(JNLPAppletLauncher.java:907)
Feb 4, 2010 12:55:49 PM org.jdesktop.applet.util.JNLPAppletLauncher displayError
SEVERE: java.io.IOException: Cannot validate certificate for CLP.dll

How can I sign .dll file ?

Any kind of help, sugeestion will be highly appriciated.