In your routine:
Public Sub MySub()
On error goto MyErrorHandler
'your code. If an error occurs it will drop into your error 'label below
Exit Sub
MyErrorHandler:
If err.Number = 68 Then
'Do stuff to handle error
msgbox "Device not present",vbcritical,"Device not found"
else
'do stuff to handle error or alert user
msgbox err.number & " " & err.description & " " & err.source
End if
End Sub