Display redirection problem

[Vincent Arnoux]

Hello,
I have a problem with Fedora Core 3 : I am unable to redirect display
with ssh -X. I get an error :

X Error of failed request:  BadAtom (invalid Atom parameter)
  Major opcode of failed request:  18 (X_ChangeProperty)
  Atom id in failed request:  0x1e5
  Serial number of failed request:  13
  Current serial number in output stream:  16


I have read somewhere that I should need to change a config file on my
server machine to enable remote display permission.
Does anyone know which file it is ?

Regards,
Vincent