"Null Pointer Exception using Read Database on jdbc:mysql"

I've had some good experience using <READ CSV>
and having a quick right-off-the-box impression what
the dataset's AVG & STDDEV might be including some
basic buble charting is basicly all, what I need.

Now I wanted to move to MySQL and seeing it's supported
via jdbc driver made me believe it could be that easy like
reading CSV files.

But using the <Read Database> Operator from RM 5.0.009
results in java NULL POINTER exception. As logged here:
--
Aug 7, 2010 7:38:46 PM INFO: Executing query: 'SELECT * FROM `test`'
Aug 7, 2010 7:38:54 PM CONFIG: Connecting to jdbc:mysql://localhost:3306/test as root.
Aug 7, 2010 7:38:54 PM CONFIG: Connecting to jdbc:mysql://localhost:3306/test as root.
Aug 7, 2010 7:38:54 PM CONFIG: Connecting to jdbc:mysql://localhost:3306/test as root.
Aug 7, 2010 7:38:57 PM SEVERE: Process failed: operator cannot be executed. Check the log messages...
Aug 7, 2010 7:38:57 PM SEVERE: Here:           Process[1] (Process)
          subprocess 'Main Process'
      ==>   +- Read Database[1] (Read Database)
Aug 7, 2010 7:38:57 PM SEVERE: java.lang.NullPointerException
--

I also tested <Stream Database> which did produce results.
Some Meta information and the data view worked as expected
using small tables like `test` from  jdbc:mysql://localhost:3306/test.

But no AVG/STDDEV & CHARTS for tables with row count
130.000 from my own  jdbc:mysql://localhost:3306/e3_1.

more detailed information:
- db source  jdbc:mysql://localhost:3306/test &
  db source  jdbc:mysql://localhost:3306/e3_1 was tested via
 different ways and allways performant & fully functional.
- Database Connection was tested successfully from RM
- used bundled 5.1.9 vs. newest mysql-connector-java-5.1.13
- running on windows xp64 3.8GB vs. 7.8GB ram
- Using RM 64Bit
- started via RapidMiner.exe or launcher.jar
- using bundled JRE vs. most current JDK SE (build 1.6.0_21-b07)
 Java HotSpot(TM) 64-Bit Server VM (build 17.0-b17, mixed mode)
- different SQL statements like:  SELECT * FROM `test`;
- different SQL statements like:  SELECT COUNT(*) FROM `test`;
- different SQL statements like:  SELECT 7 as num;

When the "run or resume current process" button is hit, RM starts
to import data while consuming more and more memory as reported
by RM's System Monitor. When peaking, the Error Message:

--
The Setup does not seam to contain any obvious errors, but you should
check the log messages or activate the debug mode in the settings
dialog in order to get more information about this problem.

                                                                                                     | OK |
--

Any hints or suggestions?

--
Best Regards
Mike