This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
(Details: serial 22 error_code 3 request_code 2 minor_code 0)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the --sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)
glad the basic KDE4 installed can run.
Running 'rpm -Va' right now before assuming something wrong with any packages.
After reinstalling all packages that fails 'rpm -V', and downgraded some packages to the packages below, I managed to back login into GNOME. Some services like Gstreamer and gnome-settings-daemon still crashes/could not start, but at least I can get back to work. Still not sure which was the culprit.