kaeru my gnome crashed , yesterday I executed the command portupgrade -a -x 'gstreamer*' its runnig for long hours every thing went fine ,but during this a power failure occurs and m/c restarted but after that  its not going to gnome asking for command login ..

and an error message 

gdm_server_spawn :Xserver not found: /usr/X11R6/bin/X : 0 -audit 0 -auth /var/gdm/ : 0.Xauth -nolisten tcp vt9