Android Question Sub timerdevice_tick

java.lang.Exception: Sub timerdevice_tick was not found.
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:219)
    at anywheresoftware.b4a.objects.Timer$TickTack.run(Timer.java:105)
    at android.os.Handler.handleCallback(Handler.java:883)
    at android.os.Handler.dispatchMessage(Handler.java:100)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7397)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:935)

Sub Class_Globals
    Public TimeGetDevice As Timer
End Sub

Public Sub Initialize(callingActivity As String)
    act = callingActivity
    TimeGetDevice.Initialize("timerDevice", 12000)
End Sub

public Sub timerDevice_Tick
    starter.timeElapsed = True   
End Sub