CDE/CDF/BTable on Pentaho 4.8 and Oracle

Hello Forum,

I'm trying (and failing) to run a dashboard with a BTable crosstab report on a Pentaho 4.8 installation (on Windows Server 2008) running against a Oracle database.
We have our data warehouse on Oracle, and we also moved Hibernate e Quartz schemas, as used by Pentaho, to the same Oracle platform.

We developed our dashboard and BTable crosstab on a lab machine in which Hibernate and Quartz were running in the default configuration (hsqldb), and, as such, they are working correctly, but as soon as we move to a production environment (full Oracle), we can't have BTable and CDE/CDF working.
We are getting this error traced in stdout.log:

11:03:53,831 ERROR [JDBCExceptionReporter] Listener refused the connection with the following error:
ORA-12519, TNS:no appropriate service handler found

Everything else (.prpt reports and Saiku analysis) work absolutely fine.

Is there any special place where jndi/jdbc connections should be configured for CDE/CDF/BTable?
Is there any "dialect" that should be selected?
Did anyone attempt to run a similar configuration before?

Stelvio.