If isNull(Me.steTimeStamp) then Me.steTimeStamp=Now() How to make it work

[survivo01]

I am trying to TimeStamp a form. I go to form properties and in BeforeUpdate I am adding an event using the example as my title.Private Sub Form_BeforeUpdate(Cancel As Integer)
If IsNull(Me.dteTimeStamp) Then Me.dteTimeStamp = Now()


End Sub

This errors and this is waht error looks like.

Also, I am supposed to put on orer by TimeStamp Access asks for paremeter
Am I doing this right.

[June7]

What is the error message?

Don't understand the second to last statement in your post.