I'm getting "attempt to index nil with Instance" can someone help?

local Dictionary = require(script.Dictionary)

local DictionaryHandler = {}

function DictionaryHandler.find(Player, action)
    return Dictionary[action][Player] --Error
end

function DictionaryHandler.add(Player, action)
    if not Dictionary[action][Player]  then
        Dictionary[action][Player] = true
    end
end

function DictionaryHandler.remove(Player, action)
    if Dictionary[action][Player] then
        Dictionary[action][Player] = nil
    end
end

return DictionaryHandler