Sword animation does not play properly in r15 humanoid, why?

So this is the problem, I had this sword been working with r6 without having any problem but now I wanted to turn it to r15, everithing is working exept for one thing. The animation. I have already switched the animations id to r15 animation but for some reason the right arm of the player freezes, like the whole animation plays exept for the right arm of your chacter... Does it have anithing to do with the animation script below? If so, whats wrong? If its not because of the script what do you guys suggest?

local Tool = script.Parent;

local walking = 0
local hold
local walk

enabled = true
function onButton1Down(mouse)
	if not enabled then
		return
	end

	local vCharacter = Tool.Parent
	local hum = vCharacter:findFirstChild("Humanoid")
    hum:LoadAnimation(script.Parent.Slash):Play()
	enabled = false
	mouse.Icon = "http://www.roblox.com/asset/?id=248193486"

	wait(1)
	mouse.Icon = "http://www.roblox.com/asset/?id=248193464"
	enabled = true

end

function onKeyDown(key)
	if walk and (key == "w") or (key == "a") or (key == "s") or (key == "d") then
		walk:Play()
		walking = walking + 1
	end
end

function onKeyUp(key)
	if walk and (key == "w") or (key == "a") or (key == "s") or (key == "d") then
		walking = walking - 1
		if walking == 0 then
			walk:Stop(0)
		end
	end
end

function onEquippedLocal(mouse)

	if mouse == nil then
		print("Mouse not found")
		return 
	end

	local vCharacter = Tool.Parent
	local humanoid = vCharacter.Humanoid

	hold = humanoid:LoadAnimation(Tool.HoldSword)
	walk = humanoid:LoadAnimation(Tool.WalkSword)

	hold:Play()

	mouse.Icon = "rbxasset://textures\\GunCursor.png"
	mouse.Button1Down:connect(function() onButton1Down(mouse) end)
	mouse.KeyDown:connect(onKeyDown)
	mouse.KeyUp:connect(onKeyUp)
end

function onUnequippedLocal()
	hold:Stop()
	walk:Stop()

	hold = nil
	walk = nil
end

Tool.Equipped:connect(onEquippedLocal)
Tool.Unequipped:connect(onUnequippedLocal)

I think you may have to make your own custom animation for the sword attack. If the sword was built for R6 it WONT work in R15. I had to recreate all my animations for my swords. The sword plugs into the Motor6D's that R6 uses but if it sees extra or less the animation completely brakes.

So I think the solution to your problem would be to create your own attack animation. Using animation editor and an R15 rig.

When you make an animation , they're couple blocks if you click on them then that part will not be animated that may be why so check your animation again.

Maybye when you do the animation you put the priority of it on action.