error cannot find quest index

Hi.
I tried to delete questions from a biologist but after when I tried starting the server I got this error:
cannot find quest index for make_herb_lv4
Assertion failed: (!"cannot find quest index"), function LoadStateScript, file questnpc.cpp, line 99.
Abort trap (core dumped)
Abort trap (core dumped)
I deleted questions from quest, states, notarget and biologist.
Sorry for my bad english,

you have to delete the questfile, then remove the lines from quest_index which should be in /usr/home/game/share/locale/germany/quest

if there is no quest_index / quest_list, upload one
and then you should give the quests rights with chmod -R 777 *
and compile them with : python make.py