Algorithm DH not available

Hi all,
   I m using J2SSH -0.2.7 for my project. I have written a subsystem
client and integrated the application with 
JWSDP-1.3 webserver. when I am calling the sshClient's connect method
with host name argument, the authentication is failing by giving the
following error.
    
KeyExchange String is diffie-hellman-group1-sha1

- The Transport Protocol thread failed
com.sshtools.j2ssh.transport.AlgorithmNotSupportedException: Algorithm
DH not available
        at com.sshtools.j2ssh.transport.kex.DhGroup1Sha1.onInit(Unknown
Source)
        at com.sshtools.j2ssh.transport.kex.SshKeyExchange.init(Unknown
Source)
        at
com.sshtools.j2ssh.transport.TransportProtocolCommon.run(Unknown Source)
        at java.lang.Thread.run(Thread.java:534)

          Can any one help me out in resolving this problem.
 

 Thanks & Regards,
 V.Sarma