TN Document Type EDIINT shows \"ERROR: The Java class f

We have installed webMethods 6.5 with EDI Packages(WmEDIINT,WmEDIforTN,WmEDI) on Solaris machine
When we open the TN console and navigate to the Documents Types screen
For TN DocumentType EDIINT following error is displayed in the Description
“ERROR: The Java class for this document type was not found”

The edint.jar,edintdoc.jar files are present in /packages/WmTN/code/jars
as well as the classes
EDIINTEnvelopeConstants.class,EDIINTEnvelopeDocType.class,EDIINTMDNEnvelopeDocType.class are present in

How to add classes in classpath and/or which classes are missing and where should I add them to solve the problem

thanks in advance
Help appreciated