Also, for future reference, if you want to pass information between modules (.lua files) within the same addon, each .lua file is "passed" two parameters, the name of the addon and a table that is exlcusive to that addon.
To use them, at the top of each file add
Code:
local addonName, addonTable = ...
the names can be anything you like.
You can create a function
Code:
function addonTable:GetMapNameByID()
...
end
Anywhere within your addon .lua files you can now call:
Code:
addonTable:GetMapNameByID()