Need help with T-Mobile GPRS

Hi all,
I have Nokia 6230 with GPRS. All drivers are installed to my PC and
Nokia PC Suite works without problems. I also have installed T-Mobile
Communication Centre.

I can not bring the GPRS connection to life. When I try to add the
device in the Communcation Centre, it finds the phone so I select it
and click continue. Network components are installed ok, modem
installation is ok, however, the 3rd (last) step ("Dial-up connections
installation") always fails. It says "Unable to install one or more of
the dial-up connections."

I've read all the PDF guides that are provided with the software but
there is nothing helpful.

Any ideas how to make this work?

Thanks a lot for any help!