Sorry I answered to Jean and I forgot to put the List in copy.
So As agreed :
NXSERVER - Version 3.5.0-8 - LESS
NXNODE - Version 3.5.0-6 - LESN
As I told Jean:
I went to try a connection to an other server with FreeNX server installed and I've got the same behavior.
I try the connection with the old NX Cleint on windows I 've no problem.
I noted OpenNXclient create in C:\Documents and Setting\users\.nx a tmp directory with 2 empty files as runlog and sshlog.
On the server with freeNX I found an empty directory /var/log/nx.
I don't have any log I'm afraid
However I prefered to focus on the freenx serverThank