cvs pserver not listening on port 2401

[Karl Lehnberger]

Following the recommendations on
  http://mia.ece.uic.edu/~papers/volans/setUpCVS.html
I set up a cvs environment on a RedHat9 Linux box (cvs-1.11.2-10).
But starting the cvs server either with
  cvs -f --allow-root=/space/cvs pserver&
or over
  xinetd
and then trying to connect from a client via
  telnet cvshost 2401
or
  cvs :pserver:address@hidden:/space/cvs login
gives the error "connection refused" which means
that the cvs process isn't even listening on port 2401.
(verified with netstat)
In /var/log/messages I found
Jun  29 14:07:11 lll cvs: error setting KEEPALIVE: Socket operation on
non-socke
t
but the cvs server is running.
What can be the reason that "cvs pserver" isn't listening on port 2401?
There is no blocking firewall or router involved.

Thank's for help
-Karl