Corrupted Jar file?

I am trying to deploy some JMF DLL's via webstart,
and it is not going well. I keep getting the message
in the JWS console..
"Corrupted JAR file at
http://www.javasaver.com/testjs/jmf/lib/win-natives.jar"

I have verifed the Jar locally, and it shows no problems.

Viz.
<Output>
D:\projects\jmf\player>jarsigner -verify -verbose -certs
lib/win-natives.jar

        1395 Sat Sep 16 20:53:48 GMT 2006 META-INF/MANIFEST.MF
        1516 Sat Sep 16 20:53:48 GMT 2006 META-INF/MEDIAPLA.SF
        1025 Sat Sep 16 20:53:48 GMT 2006 META-INF/MEDIAPLA.DSA
           0 Sat Sep 16 20:53:10 GMT 2006 META-INF/
sm 49152 Mon Apr 28 00:30:56 GMT 2003 jmacm.dll

      X.509, CN=Andrew Thompson, O=PhySci.org, L=Sydney, ST=New South
Wales, C=AU
      [certificate valid from Wed Sep 13 15:24:29 GMT 2006 to Mon Mar
05 15:24:2
......

      X.509, CN=Andrew Thompson, O=PhySci.org, L=Sydney, ST=New South
Wales, C=AU
      [certificate valid from Wed Sep 13 15:24:29 GMT 2006 to Mon Mar
05 15:24:29 GMT 2012]

  s = signature was verified
  m = entry is listed in manifest
  k = at least one certificate was found in keystore
  i = at least one certificate was found in identity scope

jar verified.
</Output>

Other notes:
a) The DLL is referenced in a JNLP that defines the
'component/library' part of the JMF (DLL's and the soundbank)
<http://www.javasaver.com/testjs/jmf/lib/jmf-pp-lib.jnlp>
(at the moment - the soundbank is commented out to
ensure that this is not a problem complicated by jar's
signed with different signatures etc.)
b) That 'library' JNLP is in turn, called by the main file at
<http://www.javasaver.com/testjs/jmf/jmstudio-pp.jnlp>
which attempts to launch JM Studio.

Any ideas what I am doing wrong?

Andrew T.