I have Java application on 6230 working with server part in java + bluecove library on XP sp2.
Also you also may consider using avetanaBluetooth. It has more complete functionality in JSR-82...

I had a problem like this on 6230.
Apperantly phone can have only one connection at a time.
So it can ran service discovery or connect to another phone but not at the same time.

Alsa my...

I have been able to do a service discovery on Nokia 6230.

Also FUY the good example of how to do this is here:
http://www.benhui.net/modules.php?name=Bluetooth

If you want to test your...

Depends on you device.
I was unable to do this on 6230

Try
http://www.benhui.net/modules.php?name=Bluetooth

I used WTK2.2 (only) on windows to start the server.
It is working but it does not use any real BT device.
I can connect application to aplication.

But when I start Nokia Connectivity Framework...