Error while deploying Processdefinition thru a servlet

[jbpmindia]

Hi
I am using 'jbpm 3.1.3' on 'JBOSS AS 4.0.5.GA'
I am executing following code in a servlet

JbpmConfiguration jbpmconfig = JbpmConfiguration.parseXmlString(
 "<jbpm-configuration>" +

 // A jbpm-context mechanism separates the jbpm core
 // engine from the services that jbpm uses from
 // the environment.

 " <jbpm-context>" +
 " <service name='persistence' " +
 " factory='org.jbpm.persistence.db.DbPersistenceServiceFactory' />" +
 " </jbpm-context>" +
 "<jbpm-context>" +
 "<service name='persistence'>" +
 "<factory>" +
 "<bean class='org.jbpm.persistence.db.DbPersistenceServiceFactory'>" +
 "<field name='isTransactionEnabled'>" +"<false/>" +"</field>" +
 "</bean>" +
 "</factory>" +
 "</service>" +
 "<service name='tx' factory='org.jbpm.tx.TxServiceFactory' />" +
 "<service name='message' factory='org.jbpm.msg.db.DbMessageServiceFactory' />" +
 "<service name='scheduler' factory='org.jbpm.scheduler.db.DbSchedulerServiceFactory' />" +
 "<service name='logging' factory='org.jbpm.logging.db.DbLoggingServiceFactory' />" +
 "<service name='authentication' factory='org.jbpm.security.authentication.DefaultAuthenticationServiceFactory' />" +
 "</jbpm-context>" +


 // Also all the resource files that are used by jbpm are
 // referenced from the jbpm.cfg.xml

 " <string name='resource.hibernate.cfg.xml' " +
 " value='hibernate.cfg.xml' />" +
 " <string name='resource.business.calendar' " +
 " value='org/jbpm/calendar/jbpm.business.calendar.properties' />" +
 " <string name='resource.default.modules' " +
 " value='org/jbpm/graph/def/jbpm.default.modules.properties' />" +
 " <string name='resource.converter' " +
 " value='org/jbpm/db/hibernate/jbpm.converter.properties' />" +
 " <string name='resource.action.types' " +
 " value='org/jbpm/graph/action/action.types.xml' />" +
 " <string name='resource.node.types' " +
 " value='org/jbpm/graph/node/node.types.xml' />" +
 " <string name='resource.varmapping' " +
 " value='org/jbpm/context/exe/jbpm.varmapping.xml' />" +
 "</jbpm-configuration>"
 );
 JbpmContext jbpmContext = jbpmconfig.createJbpmContext();
 ProcessDefinition processDefinition = ProcessDefinition.parseXmlResource("processes/WorkFlowTest/processdefinition.xml");
 jbpmContext.deployProcessDefinition(processDefinition);

In have kept 'processdefinition.xml' under processes/WorkFlowTest under WEB-INF
and I am getting the following error.

17:49:09,500 ERROR [[TestServlet]] Servlet.service() for servlet TestServlet thr
ew exception
org.jbpm.JbpmException: couldn't instantiate bean 'null' of type 'org.jbpm.tx.Tx
ServiceFactory'
 at org.jbpm.configuration.BeanInfo.createObject(BeanInfo.java:88)
 at org.jbpm.configuration.JbpmContextInfo.createObject(JbpmContextInfo.j
ava:126)
 at org.jbpm.configuration.ObjectFactoryImpl.getObject(ObjectFactoryImpl.
java:146)
 at org.jbpm.configuration.ObjectFactoryImpl.createObject(ObjectFactoryIm
pl.java:103)
 at org.jbpm.configuration.ObjectFactoryImpl.createObject(ObjectFactoryIm
pl.java:78)
 at org.jbpm.JbpmConfiguration.createJbpmContext(JbpmConfiguration.java:3
43)
 at org.jbpm.JbpmConfiguration.createJbpmContext(JbpmConfiguration.java:3
39)
 at com.test.JavaCallFlow.setjBpmConfig(JavaCallFlow.java:69)
 at com.test.TestServlet.service(TestServlet.java:20)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:252)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:173)
 at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFi
lter.java:96)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:202)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:173)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:213)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:178)
 at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(Securit
yAssociationValve.java:175)
 at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValv
e.java:74)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:126)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:105)
 at org.jboss.web.tomcat.tc5.jca.CachedConnectionValve.invoke(CachedConne
ctionValve.java:156)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:107)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav
a:148)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java
:869)
 at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.p
rocessConnection(Http11BaseProtocol.java:664)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpo
int.java:527)
 at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWor
kerThread.java:112)
 at java.lang.Thread.run(Thread.java:595)
Caused by: org.jbpm.JbpmException: couldn't load class 'org.jbpm.tx.TxServiceFac
tory'
 at org.jbpm.configuration.ObjectFactoryImpl.loadClass(ObjectFactoryImpl.
java:164)
 at org.jbpm.configuration.BeanInfo.createObject(BeanInfo.java:85)
 ... 28 more
Caused by: java.lang.ClassNotFoundException: org.jbpm.tx.TxServiceFactory
 at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoa
der.java:1355)
 at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoa
der.java:1201)
 at org.jbpm.configuration.ObjectFactoryImpl.loadClass(ObjectFactoryImpl.
java:162)
 ... 29 more

I feel it's crashing at the line
JbpmContext jbpmContext = jbpmconfig.createJbpmContext();
Pls tell what am I missing ?? It's urgent..
thanks