ssh -- X11 forwarding with new server-xfree86

[Lukas Ruf <ruf@tik.ee.ethz.ch>]

Dear all,

I updated my woody box yesterday to the newest server for XFree86 4.0.
Since then, I cannot remotely start any tools that have to connect to
the X-Client.  The error message 
  _X11TransSocketINETConnect: Can't connect: errno = 111
  Error: Can't open display: 10.0.1.4:0.0

  [1]    Exit 1                        communicator

appears even I run xhost + or I explicitely allowed the X server to
connect.

Does anyone know where I can fix the problem?  Thanks in advance for any
help.

Kind regards,

Lukas