Audit Trail

Hi,
I am trying to use Audit Trail in Access2000. I tried to look at this snippet from Microsoft. But I am getting an error when I save the record. Actually I have a form with 8 tab pages. It tracks that the change is made, even though it gives error message, but does not track which field was changed. I would appreciate if someone can help me.
Regards
K

Function AuditTrail()
On Error GoTo Err_Handler

Dim MyForm As Form, C As Control, xName As String
Set MyForm = Screen.ActiveForm

'Set date and current user if form has been updated.
MyForm!Updates = MyForm!Updates & Chr(13) & Chr(10) & _
"Changes made on " & Date & " by " & CurrentUser() & ";"

'If new record, record it in audit trail and exit sub.
If MyForm.NewRecord = True Then
MyForm!Updates = MyForm!Updates & Chr(13) & Chr(10) & _
"New Record """
End If

'Check each data entry control for change and record
'old value of Control.
For Each C In MyForm.Controls

'Only check data entry type controls.
Select Case C.ControlType
Case acTextBox, acComboBox, acListBox, acOptionGroup
' Skip Updates field.
If C.Name <> "Updates" Then

' If control was previously Null, record "previous
' value was blank."
If IsNull(C.OldValue) Or C.OldValue = "" Then
MyForm!Updates = MyForm!Updates & Chr(13) & _
Chr(10) & C.Name & "--previous value was blank"

' If control had previous value, record previous value.
ElseIf C.Value <> C.OldValue Then
MyForm!Updates = MyForm!Updates & Chr(13) & Chr(10) & _
C.Name & "==previous value was " & C.OldValue
End If
End If
End Select
Next C

TryNextC:
Exit Function

Err_Handler:
If Err.Number <> 64535 Then
MsgBox "Error #: " & Err.Number & vbCrLf & "Description: " & Err.Description
End If
Resume TryNextC
End Function