It look like the problem I have with the old quester. The script don't have enough time to see teh quest you need. One of my older machine is slower on the internet and some script don't run properly.
have a look here at line 1569. may be some number got erase. If not, yo might need to download it again.
;========== SETUP SUBS ==========
sub Initialize
set %CONTEXT_Toggle_Quest_Item 3603586
set %CONTEXT_Open_Backpack 3428334
set %QUEST_A_Simple_Bow 6415424
set %QUEST_Arch_Support 5963096