Oh, I might know this one! =)
You are creating a Cascading Event Loop.
In the Click Event for your button you are triggering the Click Event yet again. That Click Event triggers the event yet again, and so on. As each Click Event triggers the next one NONE of them actually complete execution. The Stack Space stores references to each event currently called and you call so many events that NEVER get completed that it runs out of space.
You'll get the same error with this code:
Private Sub Check1_Click()
Check1.Value = True 'assuming this is a command button
End Sub
Perhaps that simpler code will make the error and what causes it a little more clear. =)