Your MainMenuBar:SetPoint(cfg.MainMenuBar.["Position"]) would have to be spelled out to match the table, or place the table into it which doesn't line up if you have a value of a table into a table.
For example your
Code:
["Position"] = { a= "BOTTOMLEFT", Minimap, x= -515, y= -4}
Should look like this
Code:
["Position"] = { a= "BOTTOMLEFT",p= Minimap, r="CENTER", x= -515, y= -4}
Adding a 'p' for parent and an 'r' for relative point which is needed for SetPoint.
You'd also have to have your SetPoint look like this:
Code:
MainMenuBar:SetPoint(cfg.MainMenuBar.["Position"].a,cfg.MainMenuBar.["Position"].p,cfg.MainMenuBar.["Position"].r,cfg.MainMenuBar.["Position"].x,cfg.MainMenuBar.["Position"].y)
This can be simplified by just changing cfg.MainMenubar.["Position"] to a local.
Code:
local db = cfg.MainMenuBar.["Position"]
MainMenuBar:SetPoint(db.a,db.p,db.r,db.x,db.y)