Java Database Connectivity (JDBC)

Hi, I'm using Netbeans 5.5 and trying to connect to Postgres 8.1 using postgresql-8.2-505.jdbc3.jar. I'm having a problem creating EJB's from the database. I have also tried using postgresql-8.2-505.jdbc4 and postgresql-8.1-409.jdbc3

I've managed to create a connection to the database in the Databases tab in the Runtime section and I can query using that connection. I am also able to connect and query from the database from an ordinary Java Application without using the Netbeans connection tools.

The problem comes in when I try to create EJB's from the database using the wizard.
I choose "New -> Entity classes from database". I create a new datasource with the connection but it gives me the following error :
"Unable to add connection, cannot establish a connection to jdbc:postgresql://localhost:/Test using org.postgresql.Driver (Unable to find a suitable driver)"

I have placed the driver into the class path of the project and the application server. I have created a connection to a mysql database in exactly the same way and have had no problems with it.

Any suggestions?