java.lang.ClassNotFoundException: org.terracotta.session.TerracottaTomcat70xSessionValve
         at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
         at java.security.AccessController.doPrivileged(Native Method)
         at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
         at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
         at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
         at org.apache.tomcat.util.digester.ObjectCreateRule.begin(ObjectCreateRule.java:144)
         at org.apache.tomcat.util.digester.Digester.startElement(Digester.java:1276)
         at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(AbstractSAXParser.java:504)
         at com.sun.org.apache.xerces.internal.parsers.AbstractXMLDocumentParser.emptyElement(AbstractXMLDocumentParser.java:182)
         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:1320)
         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2732)
         at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:625)
         at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488)
         at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:812)
         at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:741)
         at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
         at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1208)
         at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:525)
         at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1537)
         at org.apache.catalina.startup.ContextConfig.processContextConfig(ContextConfig.java:584)
         at org.apache.catalina.startup.ContextConfig.contextConfig(ContextConfig.java:528)
         at org.apache.catalina.startup.ContextConfig.init(ContextConfig.java:787)
         at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:320)
         at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
         at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
         at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:401)
         at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:110)
         at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:139)
         at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:866)
         at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:842)
         at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
         at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:649)
         at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1581)
         at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
         at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
         at java.util.concurrent.FutureTask.run(FutureTask.java:166)
         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
         at java.lang.Thread.run(Thread.java:636)
 Jul 4, 2012 8:19:09 AM org.apache.catalina.startup.ContextConfig processContextConfig
 SEVERE: Parse error in context.xml for 
 org.xml.sax.SAXParseException; systemId: file:/usr/local/liferay/tomcat-7.0.23/conf/context.xml; lineNumber: 3; columnNumber: 109; Error at (3, 109) : org.terracotta.session.TerracottaTomcat70xSessionValve
 ....