Error? Attempt to concatenate (NON table)

ANSWERED: https://gyazo.com/6a99c74e7868f9b4e6225f3edb678837

QUESTION QUESTION QUESTION

Alright, so... My script is erroring, and in the error box it's saying:

What is the error? (Added because I need to have a question mark)

--[[
1x..3
20:03:55.332 - ServerScriptService.Main:28: attempt to concatenate local 'g' (a nil value)
20:03:55.333 - Stack Begin
20:03:55.333 - Script 'ServerScriptService.Main', Line 28 - global selectrandom
20:03:55.333 - Script 'ServerScriptService.Main', Line 38
20:03:55.333 - Stack End
]]--

Note, the script I will provide is NOT the entire script, but will be all that is needed...

function getnextpos(Table)
	local num = #Table
	local toreturn = num+1
	return(toreturn)
end

function a(z,selections)
		local x = math.random(1,#z)
		print("1x.."..x)
		for index,returned in ipairs(selections) do
			print(x)
			if x == returned then
				local y = a()
				print("y.."..y)
				return y
			end
			print("x.."..x)
			return x
		end
end

function selectrandom(location,count)
	local z = location:GetChildren()
	local selections = {}
	for i = 1,count do
		local val
		local g = a(z,selections)
		print("g = "..g)
		table.insert(selections,getnextpos(selections),g)
	end
	return(selections)
end

The issue, as I understand it, is NOT with my table, but with my returned variables, and functions I tried using a local function, but since it did not work, tried to move it out to a normal function, which also did not work. DO not worry about shortening any code you give me, as I can do that myself.

How should I fix this error?????? (Added because I "Need to have a question mark".)

Thanks, Taryo. ;)