I can try that, but i will need to try it during the weekend, because i am piled up with other work.
Yes: I think forget 1 important requirement for the server that was not listed on my DELL invoice. I think it's a ATI ES1600 GPU.
Please let me clarify further.
This same problem NOW does not occur only on CentOS 5. After multiple CentOS 5 installation failure, I fall back to installing of CentOS 4.4, (the exact version i used in the past, and work perfectly with FreeNX), this time i did the same steps too, but the server also faces the same FreeNX error.
BUT this time when i try to local login. The Server's GNOME is still there, everything work perfectly at local connection, except for the NX session. The error prompted is exactly the same as what shown on CentOS 5 too.
There is 1 thing that i suspect on why FreeNX work in the past and not now. + I think the FreeNX version in the repository has changed