Oracle Thin and IE4

I have written an applet using Oracle Thin (classes111.zip). I have my Oracle Server and my Web Server on the same machine. Everything works fine with Netscape 4.7. But with IE4 I have this message:

    java.sql.SQLException: No suitable driver     java.lang.NullPointerException

        at
com/morren/cadwin/ViewerApplet/MOConnectionLite.setSessionParameters

        at com/morren/cadwin/ViewerApplet/MOConnectionLite.connect
        at com/morren/cadwin/ViewerApplet/ViewerApplet.jbInit
        at com/morren/cadwin/ViewerApplet/ViewerApplet.init
        at com/ms/applet/AppletPanel.securedCall0
        at com/ms/applet/AppletPanel.securedCall
        at com/ms/applet/AppletPanel.processSentEvent
        at com/ms/applet/AppletPanel.processSentEvent
        at com/ms/applet/AppletPanel.run
        at java/lang/Thread.run

Can anyone explain me what it means and what I have to do ?

Thanks a lot.

                                    Ing. TOUSSET Olivier