JNDI/JDBC access issue

i am getting "javax.naming.NamingException: Cannot create resource instance" when i try to access the lookup. i am using oracle.

Context envCtx = (Context) new InitialContext().lookup("java:comp/env");
DataSource ds = (DataSource) envCtx.lookup("jdbc/TestDB"); // <---- ERROR thrown here..

my web.xml contains...

<resource-ref>
<description>DB Connection Pooling</description>
<res-ref-name>jdbc/TestDB</res-ref-name>
<res-type>oracle.jdbc.OracleDriver</res-type>
<res-auth>Container</res-auth>
</resource-ref>

i have ojdbc14.jar in the lib folder.

my server.xml contains..

<Context path="/dbcp" docBase="dbcp" debug="5"
reloadable="true" crossContext="true">

<Resource name="jdbc/TestDB" auth="Container"
type="javax.sql.DataSource" removeAbandoned="true"
removeAbandonedTimeout="30" maxActive="10"
maxIdle="30" maxWait="10000" username="xxxxxxxx"
password="xxxxxxx"
driverClassName="oracle.jdbc.driver.OracleDriver"
url="jdbc:oracle:thin:@xxxxxxxxxxxxxx"/>
</Context>

<Connector port="80" maxHttpHeaderSize="8192" maxProcessors="150"
maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
enableLookups="false" redirectPort="8443" acceptCount="150"
connectionTimeout="20000" disableUploadTimeout="true" />

Am i missing something?

Thanks