Radio System Scripts [Not Working] ?

This is the place: http://www.roblox.com/Radio-System-Test-place?id=69780965 (It's uncopy-locked so you can see whats happening.

This is the order of the Model:

--[[
    - RadioModel (Model)
        -Script (Script)
            -ScreenGui

                -FRAME (Frame)
                    -ScrollUpDown (Frame)
                        -Choice_1 (TxtButton)
                            -Script
                        -Choice_2 (TxtButton)
                            -Script
                        -Choice_3 (TxtButton)
                            -Script
                        -Choice_4 (TxtButton)
                            -Script
                        -Choice_5 (TxtButton)
                            -Script
                        -Choice_6 (TxtButton)
                            -Script
                        -Choice_7 (TxtButton)
                            -Script
                    -AudioIDInsert (TxtBox)
                    -Help (TxtButton)
                    -SubmitButton (TxtButton)
                    -AudioID (TxtLabel)

                -HELP (Frame)
                    -Done (TxtButton)
                        -Script
                    -ImageLabel (ImgLabel)
                    -Background (TxtLabel)
                    -HeadTitle (TxtLabel)
                    -Information (TxtLabel)

        -ClickPart (Part)
            -ClickDetector (ClickDetector)
            -Script
        -Music (Part)
            -Sound (Sound)
                -Script
        -Part (unnecessary)
        -Part (unnecessary)
--]]

The script below is the script in the "RadioModel.Script.ScreenGui.Frame.SubmitButton" (This Script is not working properly... Any fixes on this?) [I want the script to take the Audio ID that the player entered in the Text Box and put it at the end of "http://www.roblox.com/asset/?id=" and put it in "Sound.SoundID"

local Button = script.Parent
Frame = script.Parent.Parent


function onClick() 


Frame.Visible = false
a = script.Parent.Parent.AudioIDInsert.Text
game.Workspace.RadioModel.Music.Sound.SoundId="http://www.roblox.com/asset/?id=" .. a .. "" 

end 

Button.MouseButton1Click:connect(onClick)

The script below is the script in "RadioModel.ClickPart" (This Script is not working properly... Any fixes on this?) [I want the script to switch the visibility of the ScreenGui.Frame to true once the player clicks on the part] [I only want the GUI to be visible to the player who clicked the part ONLY though]

function onClicked(hit)
    check = hit.Parent:FindFirstChild("Humanoid")
if check ~= nil then
    local user = game.Players:GetPlayerFromCharacter(hit.Parent)

    user.PlayerGui.ScreenGui.Frame.Visible = true
    end
end
script.Parent.ClickDetector.MouseClick:connect(onClicked)

Thanks for anyone trying to help.