Paul, thanks for the hints.
Support team found what was wrong: I made a mistake at registration process. No chance to see it after that, but now it works.

<t> Last Thursday a friend and I tried to start an internet game for the first time but since then the Netplay forum says<br/>
"Unable to access Seeking Opponent database"<br/>
<br/>
Any idea what is wrong?<br/>
<br/>
Forgot to say: NetPlayReg is correct. Can it be that the server is down? Can ...