I have got the problem now...
When I create a jar file I get that error
com.ibm.etools.archive.exception.NotSupportedException: Type is unrecognized or not yet supported: PUBLIC_ID=-//Sun Microsystems, Inc.//DTD
J2EE Application 1.3//EN;SYSTEM_ID=http://java.sun.com/dtd/application_1_3.dtd
What is happening is that I am trying to deploy a Servlet 2.3 into WebSphere 4.0. Servlet 2.2 spec is supported by websphere.
What is the solution to this? Is there a patch or a jar file I need to add to application server bin directory that will accept my servlets?