Eclipse plugin: Trying to load JDBC Driver via Class.forName("...")

Hi, I'm trying to write an eclipse plugin for Social Networks'
Visualization. Therefore I need a Database Connection to an Oracle
Database. I added the Driver JAR to the classpath and did all the other
usual DB Connection stuff, but it always throws a
ClassDefNotFoundException when I try to load the Driver via
Class.ForName(...).

Any solutions? (I guess its an easy question for people used to write
eclipse plugins using external libraries ;) )

Code (called out of a MultiPageEditor via Button ActionHandler - still
a bit messed up, sorry ;) ):
------------------------------------------------
    public void generateData(Model md) {
        try {
            //DriverManager.registerDriver(new
oracle.jdbc.driver.OracleDriver());
            Class.forName("oracle.jdbc.driver.OracleDriver");
        } catch (Exception e1) {
            e1.printStackTrace();
        }
        try {
            Connection conn =
                DriverManager.getConnection("jdbc:oracle:vcoeorad/vcoe",un,pw);
                         ...........
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
--------------------------------------------------
Exception:
--------------------------------------------------
java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver
    at
org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:407)
    at
org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:352)
    at
org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:83)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClassInternal(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at util.DataImporter.generateData(DataImporter.java:40)
    at snv.ui.GeneratorComposite$1.mouseDown(GeneratorComposite.java:95)
    at
org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:133)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:928)
    at
org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3348)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:2968)
    at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:1914)
    at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:1878)
    at
org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:419)
    at
org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
    at
org.eclipse.ui.internal.ide.IDEApplication.run(IDEApplication.java:95)
    at
org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:78)
    at
org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:92)
    at
org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:68)FEHLER
BEIM LADEN DES TREIBERS!
---------------------------------------------

Please help! :) Rescuer gets a beer when in Vienna!

Gg