OnTime Procedure 'Not Found'

In trying to set up a structure for a bigger and better worksheet, I've come up against a problem that doesn't make sense to me: When the Worksheet is activated, the startTimer sub is in fact run with the OnTime application. But I keep getting the error message "Macro MakeNote not found," when that macro is in fact right there.

The code is very simple:

Sub Worksheet_Activate()
startTimer
End Sub

Sub startTimer()
Application.OnTime Now + TimeValue("00:00:01"), "MakeNote"
End Sub

Sub MakeNote()
ActiveSheet.Cells(6, 5).Value = "YES"
End Sub

Sub TimerExpired()
checkNewBar
End Sub

Sub checkNewBar()
ActiveSheet.Cells(4, 1).Value = "123"
End Sub

A second question: witll the TimerExpired macro run all by itself when the Timer expires, or do I need to do something special ?