500 Servlet Exception

java.lang.NoClassDefFoundError: org/apache/xerces/parsers/DOMParser
	at java.lang.Class.getDeclaredMethods0(Native Method)
	at java.lang.Class.privateGetDeclaredMethods(Class.java:1647)
	at java.lang.Class.getDeclaredMethods(Class.java:1131)
	at java.beans.Introspector$1.run(Introspector.java:1126)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.beans.Introspector.getPublicDeclaredMethods(Introspector.java:1124)
	at java.beans.Introspector.getTargetMethodInfo(Introspector.java:989)
	at java.beans.Introspector.getBeanInfo(Introspector.java:370)
	at java.beans.Introspector.getBeanInfo(Introspector.java:144)
	at java.beans.Introspector.getBeanInfo(Introspector.java:205)
	at java.beans.Introspector.<init>(Introspector.java:351)
	at java.beans.Introspector.getBeanInfo(Introspector.java:144)
	at com.caucho.jsp.JavaGenerator.addBeanClass(JavaGenerator.java:2012)
	at com.caucho.jsp.JavaGenerator.generateUseBean(JavaGenerator.java:1454)
	at com.caucho.jsp.JavaGenerator.generateTag(JavaGenerator.java:804)
	at com.caucho.jsp.JspGenerator.generateChildren(JspGenerator.java:886)
	at com.caucho.jsp.JspGenerator.generate(JspGenerator.java:315)
	at com.caucho.jsp.JspParser.parse(JspParser.java:329)
	at com.caucho.jsp.JspParser.parse(JspParser.java:234)
	at com.caucho.jsp.JspManager.createPage(JspManager.java:172)
	at com.caucho.jsp.PageManager.getPage(PageManager.java:351)
	at com.caucho.jsp.PageManager.getPage(PageManager.java:206)
	at com.caucho.jsp.QServlet.getPage(QServlet.java:220)
	at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:129)
	at com.caucho.server.http.Invocation.service(Invocation.java:315)
	at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
	at com.caucho.server.http.QRequestDispatcher.include(QRequestDispatcher.java:364)
	at com.caucho.server.http.QRequestDispatcher.include(QRequestDispatcher.java:275)
	at com.caucho.jsp.QPageContext.include(QPageContext.java:550)
	at _index__jsp._jspService(/index.jsp:124)
	at com.caucho.jsp.JavaPage.service(JavaPage.java:75)
	at com.caucho.jsp.Page.subservice(Page.java:506)
	at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:182)
	at com.caucho.server.http.Invocation.service(Invocation.java:315)
	at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
	at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
	at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
	at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
	at java.lang.Thread.run(Thread.java:534)