Java Database Connectivity (JDBC)

I had web app working under netbeans 4.1.
I tried rebuilding it under netbeans 5.0, but now get the error:
Cannot load JDBC driver class 'oracle.jdbc.driver.OracleDriver'
when I try to connect to the database.

The connection code is as follows:

Context ctx = new InitialContext( );
DataSource ds = (DataSource) ctx.lookup("java:/comp/env/jdbc/devarch");
this.Conn = ds.getConnection();

The resource is defined in contect.xml as follows:

<Resource name="jdbc/devarch"
auth="Container"
type="javax.sql.DataSource"
maxActive="100"
maxIdle="30"
maxWait="10000"
username="archive_app"
password="archive_app"
driverClassName="oracle.jdbc.driver.OracleDriver"
url="jdbc:oracle:thin:@warch2.cmc.int.ec.gc.ca:1521:devarch"/>
</Context>

Werner