Authentication failure with freenx on FC6

[Pelusa]

Dear Fedora community,
I know there are several threads around regarding this topic but none of it did help, and i am a newbie to FC and freenx, thats why i hope you can help me.
First of all, I had freenx running! In addition I had an open VNC connection and noticed that the nx-connection uses a virtual display, so that multiple users logging in would not see the same thing. Unfortunately i played around with tty and changed it (I forgot the exact command something chng... and then a number for different displays, i guess), and suddenly everything was black .... it took me a while to get vnc running again and get the displays to the defaults, but NX would not work any more. I uninstalled it therefore with rpm -e freenx. This was a mistake!!. because now, after reinstalling freenx (yum install freenx), I cannot get access any more.
This is the error massage i get (client is a Mac OSX, the NoMachine client):

NX> 203 NXSSH running with pid: 1548
NX> 285 Enabling check on switch command
NX> 285 Enabling skip of SSH config files
NX> 285 Setting the preferred NX options
NX> 200 Connected to address: xxx.xxx.xxx.xx on port: 22
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
NX> 204 Authentication failed.

Let me tell you, what i already did:
I transferred the the client key
opened in sshd_config and node_conf (had to cp from node_conf.sample) port 22
changed in sshd_config the .ssh/authorized_keys to /home/'username'/.ssh/authorized_keys2
opened PubkeyAuthentication yes
passwd -fu nx as it was locked

so now I have no glue what I should do. I can ssh to the FC6 machine, no problem. But the nx-connection fails. I am really frustrated after three days of googeling and trying to get it run! I am just not proficient with linux at all .... obviously ...

And just an aside, if this problem is solved, i would appreciate it if anybody could help to configure freenx so that I can see the native screen rather than a virtual new desktop

Thanks already in advance, and hopefully somebody knows where my mistake is.
Thomas