I am not coder. I get error.

plugins/NavComp/data/tools.lua:133: attempt to call method 'lower' (a nil value)
stack traceback:
plugins/NavComp/data/tools.lua:133: in function 'SyncSectorNotes'
plugins/NavComp/data/data.lua:218: in function 'func'
vo/vo_event.lua:28: in function <vo/vo_event.lua:26>
[C]: in function 'xpcall'
vo/vo_event.lua:87: in function '_do_event'
vo/vo_event.lua:108: in function 'ProcessEvent'
vo/vo_gameevent.lua:1066: in function 'InitializeStation'
vo/vo_gameevent.lua:1177: in function 'complete_cb'
vo/vo_ge_station.lua:407: in function 'CheckForCompletedTransaction'
vo/vo_ge_station.lua:449: in function 'SetTransactionWantCount'
vo/vo_ge_station.lua:571: in function 'func'
vo/vo_gameevent.lua:2296: in function <vo/vo_gameevent.lua:2288>

Lua show

-- Update the anchor sector list
for sysId=1, #SystemNames, 1 do
notes = SystemNotes [sysId]
for targetId, note in pairs (notes) do
-- Check for manual avoids
if string.find (note:Lower (), "#avoid:") then
if not avoids [targetId] then
-- new avoid, clear system from cache
navcomp.data.stressMaps [GetSystemID (targetId)] = nil
end
navcomp.data.avoidSectors [targetId] = "YES"
end

I dont know how fix. Please help.

find file tools.lua under the data subdirectory and open it witha text editor
aound line 136 you will find these lines

for targetId, note in pairs (notes) do
-- Check for manual avoids
if note == nil or type (note) == "table" then note = " " end -- Add this line here
if string.find (note:lower (), "#avoid:") then
-- Found avoid, checking if already recorded
tempNav [targetId] = nil

save the file and restart game... problem should be gone.
Not sure if I fixed the actual problem but it will get rid of the errors....