The error says that playergui isn't a valid member?

Help, I tried making a script that breaks the enemies leg but when it ends up picking the number then the script says that PlayerGui isn't a valid member of Player

function legbreak()
local legbreak = math.random(1, 3)
if legbreak == 1 then
local chr = hit.Parent
local plr = game.Players:GetPlayerFromCharacter(chr)
print(plr.Name)
wait(RoF)
plr.PlayerGui.GUI.Data.legbroken.Value = true
hit.Humanoid.WalkSpeed = 10
plr.PlayerGui.GUI.HUD.BrokenLeg.Visible = true
print("Yes")
elseif legbreak == 2 then
print("No")
elseif legbreak == 3 then
print("No")
end
end

A few errors:

function legbreak(hit) -- Needs to know what hit is. I declared it here.
local legbreak = math.random(1, 3)
if legbreak == 1 then
local chr = hit.Parent
local plr = game.Players:GetPlayerFromCharacter(chr)
print(plr.Name)
wait(RoF)
plr.PlayerGui.GUI.Data.legbroken.Value = true
hit.Humanoid.WalkSpeed = 10
plr.PlayerGui.GUI.HUD.BrokenLeg.Visible = true
print("Yes")
elseif legbreak == 2 then
print("No")
elseif legbreak == 3 then
print("No")
end
end
script.Parent.Touched:connect(legbreak) -- Calls the function.

The rest looks about right :) Hope I helped.