java.lang.NoClassDefFoundError: (Class Name)

I'm running a jar file consisting of java classes in a groovyscript. I run the below code and get the error in the Subject heading of this post. Any ideas what's wrong? If it helps the class name that brings the error is a Java Class, XML Accessor Type and XML Type whereas all the other classes are just Java Classes

import com.lmig.automation.framework.*;

com.lmig.automation.framework.reporting.alm.ConnectionManager connectionMgr = new com.lmig.automation.framework.reporting.alm.ALMConnectionManager();
com.lmig.automation.framework.reporting.alm.RequestProcessor requestProcessor = new com.lmig.automation.framework.reporting.alm.ALMRequestProcessor(connectionMgr);
com.lmig.automation.framework.reporting.alm.Reporter reporter = new com.lmig.automation.framework.reporting.alm.ALMReporter(requestProcessor);

def date = new Date().getTime();
def map = [testLabId:"831431", currentTime:date, testCaseName:'Test1', status:'Failed'];

println reporter.updateTestInstance(map);