Script works once then errors the second time?

This code works fully the first time then the second time I enter the code, it goes into the 'Error' function and says code isnt found. I entered the same code twice and it still didnt work the second time. Does anyone have any ideas to help?

Code=0
Dest=""
Via=""
Num=""
chnger=script.Parent.Changer.SurfaceGui.Frame

function Set()
    Code=script.Parent.Changer.SurfaceGui.Frame.Num.Text
    if script.Parent.DestCode.Value=="99" then
        Num="T1"
        Dest="Tester1"
        Via="T3"
        Cont()
    elseif Code=="0" then
        Num="T2"
        Dest="Tester2"
        Via="T4"
        Cont()
    else
        Error()
    end
end

function One()
    chnger.Num.Text=chnger.Num.Text..'1'
end
function Two()
    chnger.Num.Text=chnger.Num.Text..'2'
end
function Three()
    chnger.Num.Text=chnger.Num.Text..'3'
end
function Four()
    chnger.Num.Text=chnger.Num.Text..'4'
end
function Five()
    chnger.Num.Text=chnger.Num.Text..'5'
end
function Six()
    chnger.Num.Text=chnger.Num.Text..'6'
end
function Seven()
    chnger.Num.Text=chnger.Num.Text..'7'
end
function Eight()
    chnger.Num.Text=chnger.Num.Text..'8'
end
function Nine()
    chnger.Num.Text=chnger.Num.Text..'9'
end
function Zero()
    chnger.Num.Text=chnger.Num.Text..'0'
end

function Error()
    chnger.Frame.Dest.Text="CODE NOT VALID"
    chnger.Frame.Num.Text=" "
    print("Code: "..script.Parent.DestCode.Value.." is not valid")
    chnger.Num.Text=" "
    wait(2)
    chnger.Frame.Dest.Text=" "
end

function Cont()
    script.Parent.FrontDest.SurfaceGui.Frame.Dest.Text=Dest
    script.Parent.FrontDest.SurfaceGui.Frame.Num.Text=Num 
    script.Parent.FrontDest.SurfaceGui.Frame.Via.Text="Via "..Via
    script.Parent.SideDest.SurfaceGui.Num.Text=Num
    script.Parent.SideDest.SurfaceGui.Dest.Text=Dest
    script.Parent.RearNum.SurfaceGui.Dest.Text=Num  
    chnger.Frame.Dest.Text=Dest
    chnger.Frame.Num.Text=Num
    chnger.Num.Text=" "
    print("Complete")
end



chnger.Enter.MouseButton1Click:connect(Set)
chnger.One.MouseButton1Click:connect(One)
chnger.Two.MouseButton1Click:connect(Two)
chnger.Three.MouseButton1Click:connect(Three)
chnger.Four.MouseButton1Click:connect(Four)
chnger.Five.MouseButton1Click:connect(Five)
chnger.Six.MouseButton1Click:connect(Six)
chnger.Severn.MouseButton1Click:connect(Seven)
chnger.Eight.MouseButton1Click:connect(Eight)
chnger.Nine.MouseButton1Click:connect(Nine)
chnger.Zero.MouseButton1Click:connect(Zero)