Why is this giving me this error [TEXTBOX/FOCUSLOST] ?

local succ = false;
script.Parent.FocusLost:connect(function(enter)
	if game.Players.LocalPlayer.IsRapper.Value then script.Parent.Text = "You cant change names during rap" wait(2) script.Parent.Text = game.Players.LocalPlayer.RapperName.Value return end
	if enter then
		if script.Parent.Text == "" or not script.Parent.Text then return end
		if #script.Parent.Text>35 or #script.Parent.Text < 1 or #script.Parent.Text:match("%W+") == #script.Parent.Text then --ERRORS HERE

The error is "attempt to get length of a nil value"

I'm just wondering how script.Parent.Text is possible to be nil when the line before that literally should filter that away.

The problem is your :match() call. The match is returning nil, which is where your error is coming from.

What are you trying to do with that line?