Cannot connect to MySql database

Hi,

I'm using soapui-3.5 Open Source and added a "JDBC Request" to my testcase.

Before starting soapUI I've added the mysql driver to \bin\ext directory (mysql-connector-java-5.1.12-bin.jar)

Following fields are entered:
- Driver: com.mysql.jdbc.Driver
- Connection String: jdbc:mysql://localhost:3306/testschema?user=root&password=root
(no sql query created yet)

Then I press "Test Connection" but I receive an error popup:
"Can't get the connection for specified properties, java.lang.NullPointerException"

Establishing a connection within java (using Eclipse) with the same database and driver works fine.

Any idea what the problem could be?

Regards,
Leonidas