Database Software

First of all, sorry if my english is not soo good.

Weel, I had installed MapViewer im my computer. The OC4J is installed adn running perfectly.
However, I can4t execute the servlet at URL http://localhost:8888/mapviewer/omserver. When I try the following error message appears:

500 Internal Server Error
java.lang.NoClassDefFoundError: oracle/xml/util/XMLException
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.HttpApplication.loadServlet(HttpApplication.java:1520)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.HttpApplication.findServlet(HttpApplication.java:3723)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.HttpApplication.getRequestDispatcher(HttpApplication.java:1996)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:444)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:189)
at com.evermind[Oracle9iAS (1.0.2.2.1) Containers for J2EE].util.ThreadPoolThread.run(ThreadPoolThread.java:62)

The "MapViewer Users Guide" say that this message means that the MapViewer is not working and was not succesfully installed. But the URL http://localhost:8888/mapviewer works perfectly and display a page named "Admin & Map Request Forms".

What can be wrong ?

Thanks,

Rodrigo