Why is tonumber not converting my string?

-- SOLVED -- I had made a stupid mistake with "Pack1 = script.Parent" because the numbered TextButtons are actually script.Parent.Pack1!

Hi guys. I have this script that changes a decal depending on if a player has completed a level. All of the children of Pack1 are numbered 1 through to 12. This script has broken as I have commented down below.

Help much appreciated!

while true do
	wait(2)
	LevelsCompleted = game.Players.LocalPlayer.LevelsCompleted
	Pack1 = script.Parent:GetChildren()
	
	for i,child in pairs(Pack1) do
		Level = tonumber(child.Name) 
		if Level <= LevelsCompleted.Value then -- this line errors. It says "cannot compare string with a number" or something similar.
			child.ImageLabel.Image = "http://www.roblox.com/asset?id=173263900"
		elseif (Level + 1) == LevelsCompleted.Value then
			child.ImageLabel.Image = "http://www.roblox.com/asset?id=173701607"
		else
			child.ImageLabel.Image = "http://www.roblox.com/asset?id=173701600"
			
		end
	end
	
end

Check if the child's name is not a string...

while true do
    wait(2)
    LevelsCompleted = game.Players.LocalPlayer.LevelsCompleted
    Pack1 = script.Parent:GetChildren()

    for i,child in pairs(Pack1) do
	if tonumber(child.Name)  ~= nil then --Checks if the name is not a string.
        Level = tonumber(child.Name) 
        if Level <= LevelsCompleted.Value then -- this line errors. It says "cannot compare string with a number" or something similar.
            child.ImageLabel.Image = "http://www.roblox.com/asset?id=173263900"
        elseif (number + 1) == LevelsCompleted.Value then
            child.ImageLabel.Image = "http://www.roblox.com/asset?id=173701607"
        else
            child.ImageLabel.Image = "http://www.roblox.com/asset?id=173701600"

        end
    end
	end

end

Sorry if this doesn't work, if it doesn't then i'll try look for a solution.