tomcat updata problem

[ZHOU Ping C]

hello all:
  I bulid a project  use tomcat+struts+hibernate. The develop tool is
MyEclipse

  At beginning I use tomcat 4.1 , jdk 1.4 and hibernate 2.0 , the
project works well.
 
  Recently I updata tomcat from 4.1 to  5.5.23  and jdk from 1.4  to
1.6, some errors come out.

  The errors as follows:

   ERROR [http-8080-1] (ApplicationDispatcher.java:723) -
Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: Attempted a bean operation on a null
object.
 
........................................................................
.......................................................................
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
        at      at java.lang.Thread.run(Thread.java:619)
 
 Can anybody help me?

  Thanks