WSIFWSDLFactoryImpl error

[xm bobd988]

Hi,
I am trying to use a web service  to receive message and inoke  to  another 
web services. But I kept getting the below errors when invoking the web 
services,

WSDLException: faultCode=CONFIGURATION_ERROR: Problem instantiating factory 
implementation.: org.apache.wsif.wsdl.WSIFWSDLFactoryImpl: 
java.lang.ClassNotFoundException: org.apache.wsif.wsdl.WSIFWSDLFactoryImpl
at 
org.apache.catalina.loader.StandardClassLoader.loadClass(StandardClassLoader.java:854)

	at 
org.apache.catalina.loader.StandardClassLoader.loadClass(StandardClassLoader.java:721)

        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:141)
        at javax.wsdl.factory.WSDLFactory.newInstance(Unknown Source)
        at MessageHandler.testWsif(MessageHandler.java:61)
...

Here is my code for invoking the webservice ,
...
 
WSIFPluggableProviders.overrideDefaultProvider("http://schemas.xmlsoap.org/wsdl/soap/";, 
new WSIFDynamicProvider_ApacheAxis());
   System.out.println("Reading WSDL document from '" + wsdlLocation + "'");
   try
   {
   //org.apache.wsif.wsdl.WSIFWSDLFactoryImpl ();
   WSDLFactory factory = 
WSDLFactory.newInstance("org.apache.wsif.wsdl.WSIFWSDLFactoryImpl");
    Definition def = factory.newDefinition(); // test line
   Definition def1 = org.apache.wsif.util.WSIFUtils.readWSDL(null, 
wsdlLocation); //test

   }
   catch(WSDLException e)
   {
     e.printStackTrace();
   }
   System.out.println("Preparing WSIF dynamic invocation");
...
However, with the same wsdl4j.jar and wsif. jar, the above code works fine 
from a non-servlet client, but once put into servlet( in my case, web 
service API), the error happened.

I use the Jbuilder 2005, Tomcat 5.0.28, wsif.jar ( from 2.0 release), 
wsdl4j.jar

Have anyone experienced this issue before, how to solve this? Thanks.
Bob