I have a procedure to log changes to certain fields in a form.
If I modify an existing record, everything works great, but if I am adding a new record  I get the following:

Run Time Error '94':
Invalid Use of Null

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Private Sub StatusCombo_BeforeUpdate(Cancel As Integer)
    
    LogIt Forms!FPR03aTasks!TPR02aSubProjName, TPR03aTskDescription, StatusCombo.OldValue, StatusCombo.Column(1), "", "", TPR03aTskID
  
    
End Sub
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Public Sub LogIt(TPR04aSubApp As String, TPR04aDesc As String, TPR04aStatFrom As String, TPR04aStatTo As String, TPR04aPrtyFrom As String, TPR04aPrtyTo As String, TPR04aRecID As String)
    
    
    Dim S As String

    S = "INSERT INTO TPR04aChgLog (TPR04aSubApp, TPR04aDesc, TPR04aStatFrom, TPR04aStatTo, TPR04aPrtyFrom, TPR04aPrtyTo, TPR04aRecID) " & _
            "Values (""" & TPR04aSubApp & """, """ & TPR04aDesc & """, """ & TPR04aStatFrom & """, """ & TPR04aStatTo & """, """ & TPR04aPrtyFrom & """, """ & TPR04aPrtyTo & """, """ & TPR04aRecID & """)"
        
   DoCmd.SetWarnings False
   DoCmd.RunSQL S
   DoCmd.SetWarnings True
  
End Sub
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