JBPM4.4 및tomcat6.0.X 호환 문제

JBPM4 기반 웹 프로젝트 jsp 페이지에서 다음과 같은 오류가 발생했습니다.
      
exception

javax.servlet.ServletException: java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.servlet.jsp.JspApplicationContext.getExpressionFactory()Ljavax/el/ExpressionFactory;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/OnDuty/wfmanage_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspApplicationContext, have different Class objects for the type javax/el/ExpressionFactory used in the signature
 org.apache.jasper.servlet.JspServlet.service(JspServlet.java:275)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

 
root cause

java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.servlet.jsp.JspApplicationContext.getExpressionFactory()Ljavax/el/ExpressionFactory;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/OnDuty/wfmanage_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspApplicationContext, have different Class objects for the type javax/el/ExpressionFactory used in the signature
 org.apache.jsp.OnDuty.wfmanage_jsp._jspInit(wfmanage_jsp.java:27)
 org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:52)
 org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:159)
 org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:329)
 org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
 org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

 WEB-INF\lib jar (juel.jar, juel-engine.jar, juel-impl.jar) tomcat6 lib jar (el-api.jar) 

 ：

 ： tomcat5.5  

 ： juel.jar, juel-engine.jar, juel-impl.jar tomcat6 lib ， el-api.jar， WEB-INF\lib juel.jar, juel-engine.jar, juel-impl.jar 。 。