Got Oracle JDBC thin to work.
Oracle has changed the package.class name of its driver from jdbc.oracle.driver.OracleDriver to jdbc.oracle.OracleDriver, but RapidMiner5 is still looking for the old reference.
The wiki needs an update (forum account != wiki account?):
Documentation on Oracle package.class change:
This thread helped a bit but did not identify the recent change:
The workaround is to use the Tools > Manage Database Drivers > Add wizard to help build a custom jdbc_properties.xml file.
Hope this helps.