Problem with WAS 6.1 Data Source Creation

Hi,
I Installed WAS 6.1 trial version and tried to create a Data Source in it.
I created a JDBC provider for ORACLE
Type: Oracle Connection Pool data Source

It showed the implementation class:
oracle.jdbc.pool.OracleConnectionPoolDataSource

When i create the data source with this provider and try to test the connection i get the following error:

The test connection operation failed for data source CARTS_DS on server server1 at node 01hw139182Node01 with the following exception: java.sql.SQLException: java.lang.IncompatibleClassChangeError.

Can anyone help Please
Thanks in advance