This is how i looped mine but its still not working! and i waited 5 secs.
wait(5)
local musicholder = Instance.new("Model")
musicholder.Parent = game.Workspace
musicholder.Name = "MusicPlayingModel"
local musicplayer = Instance.new("Sound")
musicplayer.Parent = game.Workspace.MusicPlayingModel
musicplayer.SoundId = "http://www.roblox.com/asset/?id=182079456"
musicplayer.Looped = true
musicplayer:Play()

2 comments
Did the Audio play at all? Did you leave the Studio while it was playing? Was there any errors? These questions are important. As you may not have known, Line 10 is NOT necessary! 'Instance.new' has a second, optional Argument! Also, getting the Model from the Workspace is not necessary, and is not needed, get the Model from it's Variable!
Isn't there a loop setting on the sound object? This isn't even a scripting question.