Yes, the the process is actually there although it doesn't show itself. I haven't running xhost. And i can run any gnome based software correctly. Another syndrome: some windows show but don't repaint. For example, kcalc show its main window. But if you move the window or try to select a menu, the window do not response and can only be forced to quit.
My linux server runs on redhat centos. I can use kde and other qt-based software remotely with vncserver/vncviewer. The problem is : most software can't start correctly when i login locally on the server, even the konsole. Nothing will happen when the cursor stops jumping. What's wrong with the kde enviroment or qt lib. BTW:I havn't made any special configuration. just atuo-update it periodically.