Getting error when we create the JCO connection

Hi All, We are getting the following error , when we connected the JCO connection.

Can any body guess it what is the cause of this error

com.sap.mw.jco.JCO$Exception: (102) RFC_ERROR_COMMUNICATION: Connect to message server host failed Connect_PM TYPE=B MSHOST=eimkopdvs1 GROUP=PRD R3NAME=EIT MSSERV=sapmsEIT PCS=1 ERROR service '?' unknown TIME Wed Oct 18 16:10:35 2006 RELEASE 640 COMPONENT NI (network interface) VERSION 37 RC -3 COUNTER 1