So im using this code to create time stamps

Code:
Private Sub Worksheet_Change(ByVal Target As Range)'Check is column J (10)
If Not Target.Column = 10 Then Exit Sub
'Check is single cell entry
If Not Target.Cells.Count = 1 Then Exit Sub
'otherwise datestamp K in same row
Target.Offset(0, 1) = Now
End Sub
However I want to repeat this with column N and O

I tried to create my own code in notepad, This is what i came up with

Code:
Private Sub Worksheet_Change(ByVal Target As Range)
'Check is column N (10)
If Not Target.Column = 10 Then Exit Sub
'Check is single cell entry
If Not Target.Cells.Count = 1 Then Exit Sub
'otherwise datestamp O in same row
Target.Offset(0, 1) = Now
End Sub

However its coming up with "Compile Error Ambiguous name detected worksheet_change"

what am i doing wrong ?