Erro ao startar o tomcat no myeclipse

Olá amigos,

 Estou tendo o seguinte problema, sempre usei o lomboz como plugin para editar as páginas jsp e agora baixei o plugin myeclipse, fiz todas as configurações possíveis. Mais quando eu tento startar o tomcat pelo myeclipse ocorre o erro mensionado abaixo. Estou usando o eclipse 3.0.0 e o plugin myeclipse 3.0.x.
 Agradeço pela ajuda.

10 [main] ERROR digester.Digester - Begin event threw exception
java.lang.ClassNotFoundException: org.apache.catalina.core.StandardServer
at java.net.URLClassLoader$1.run(URLClassLoader.java:199)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
at org.apache.commons.digester.ObjectCreateRule.begin(ObjectCreateRule.java:252)
at org.apache.commons.digester.Digester.startElement(Digester.java:1237)
at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.startElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentScannerImpl$ContentDispatcher.scanRootElementHook(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.commons.digester.Digester.parse(Digester.java:1495)
at org.apache.catalina.startup.Catalina.start(Catalina.java:449)
at org.apache.catalina.startup.Catalina.execute(Catalina.java:400)
at org.apache.catalina.startup.Catalina.process(Catalina.java:180)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:203)
Catalina.start: java.lang.ClassNotFoundException: org.apache.catalina.core.StandardServer
java.lang.ClassNotFoundException: org.apache.catalina.core.StandardServer
at org.apache.commons.digester.Digester.createSAXException(Digester.java:2312)
at org.apache.commons.digester.Digester.createSAXException(Digester.java:2332)
at org.apache.commons.digester.Digester.startElement(Digester.java:1240)
at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.startElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentScannerImpl$ContentDispatcher.scanRootElementHook(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.DTDConfiguration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.commons.digester.Digester.parse(Digester.java:1495)
at org.apache.catalina.startup.Catalina.start(Catalina.java:449)
at org.apache.catalina.startup.Catalina.execute(Catalina.java:400)
at org.apache.catalina.startup.Catalina.process(Catalina.java:180)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:203)