Song Handler Attempt to concatenate field?

Heya!

So Im making a Trello Music System and I keep receiving this error:

http://prntscr.com/g2a9oj

I have tried multiple things and cant seem to find a fix, its driving me insane!

Here is the code within the error:

while wait() do		
	SongNum = SongNum+1
	local RawSong = Songs[SongNum]
	local Song = "http://www.roblox.com/asset/?id="..Songs[SongNum]
	if Song ~= LastSong then
		game:GetService("ContentProvider"):Preload(Song)
		local Sound = Instance.new("Sound", game.Workspace)
		Sound.Volume = 1
		Sound.SoundId = Song
		Sound:Play()
		game.ReplicatedStorage.Events.SongChanged:FireAllClients(game:service('MarketplaceService'):GetProductInfo(tonumber(RawSong)).Name)
		wait(120)
		Sound:Stop()
		wait()
		Sound:remove()
		NotPlaying = false
	else
		NotPlaying = false			
	end
end