No, I think nocturna_gr means that there are no entries in the layouts list that can be added.
I have the same problem in KDE 3.2. Maybe it's a bug.
I solved that problem by modifying xorg.conf file.
Code:
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "si,sr"
Option "XkbOptions" "grp:alt_shift_toggle,grp_led:scroll"