also very important... turn off the error handling with On Error GoTo 0
Code:
Private Sub SoSomething()

    On Error GoTo errHandler

    'Do some stuff that may cause an error

    On Error GoTo 0

    'Do some stuff that you don't want to test for an error

    Exit Sub 'Exit the sub before falling into the error handler

errHandler:
'Handle the error here

End Sub