Hi,
I believe your problem is that the certificate is a client one. The only time I've seen that error was when we were missing a server certificate - the one that is used to authenticate the server rather than the one used to authenticate the client. The certificate that, say, IE asks you whether you want to install when you visit a https URL is a server certificate.
I'm guessing this based on the command line 'client.cer' reference. Try with the server certificate in your keystore and see if the error is still there, if it is then double check the certificate (certificate CN should be equal to the hostname IIRC but you can get around that sometimes by munging the hosts file on your client... hack hack hack)
HTH,
Tom
