Lua Scripting • I despair to find the error in LUA

Code:

local cng_Value = SKIN:GetVariable('cng_Value')local z_s_cng= SKIN:GetVariable('cng_Field')local z_cng = tonumber(string.match(z_s_cng, "z(.-)_"))local s_cng = tonumber(string.match(z_s_cng, "s(.*)$"))-- File pathlocal file = "dayly_todo.txt"local base_dir = SKIN:GetVariable('path')local file_path = base_dir .. file-- Open file in read-write modelocal read_file = io.open(file_path, "w")-- reads file in an arraylocal zeilen = {}if read_file then    for line in read_file:lines() do  -- Read file line by line and store the lines in an array        local einzelwerte = {}        for wert in line:gmatch("[^~]+") do            table.insert(einzelwerte, wert)  -- Insert the individual values ​​into the inner array        end        table.insert(zeilen, einzelwerte)  -- Insert the array of single values ​​into the main array    endend--Initialize data variablelocal data = ""-- write the lines including changed data into the variable datafor z, einzelwerte in ipairs(zeilen) do    for s, wert in ipairs(einzelwerte) do        if s == s_cng and z == z_cng then             data = data .. "~" .. cng_Value  -- writes the changed value it in the line        else            data = data .. "~" .. wert  --writes the previous value into the line        end    end    data = string.sub(data, 1, -2)  -- Removes the last character ~    data = data .. "\n" -- adds a line break at the end of the lineendif write_file then    write_file:write(data)  -- Write the variable data into the fileendwrite_file:close() -- Close fileSKIN:Bang('!Refresh')

Code:

ASS 100~1~1~1~1~1~1~1~6:30Rosuvastatin~1~1~1~1~1~1~1~6:30Pantoprazol (1h v Essen)~1~1~1~1~1~1~1~17:00Vit. D+K~0~0~0~0~0~0~1~10:00