I keep getting an error message when trying to make two beams loop, any help?

Hey, im trying to make a script where its a looping animation of two beams changing textures and transparency, but I keep getting this error message:

14:48:27.113 - Workspace.smileghost.Script:3: bad argument #3 to 'Transparency' (NumberSequence expected, got number)

is there something im doing wrong? heres the script:

while true do
    wait(0.1)
    script.Parent.Head.Beam.Transparency = 1
    script.Parent.Head.OtherBeam.Texture = "http://www.roblox.com/asset/?id=4745838158"
    script.Parent.Head.OtherBeam.Transparency = 0
    wait(0.1)
    script.Parent.Head.OtherBeam.Transparency = 1
    script.Parent.Head.Beam.Transparency = 0
    wait(0.1)
    script.Parent.Head.Beam.Transparency = 1
    script.Parent.Head.OtherBeam.Texture = "http://www.roblox.com/asset/?id=4745838502"
    script.Parent.Head.OtherBeam.Transparency = 0
    wait(0.1)
    script.Parent.Head.OtherBeam.Transparency = 1
    script.Parent.Head.Beam.Transparency = 0
end