IF loop: object variable or with block variable not set

[dagerr]

Hi, the following code work properly but after end it shows error in IF loop: object variable or with block variable not set. I don't know what is not set. Help me please.

Sub add_sign_xml()


Dim bPar As Range
Dim oPar As Paragraph
  Set bPar = ActiveDocument.Range
 
  With bPar.Find
    With .Font
    .Size = 8
    .Underline = wdUnderlineSingle
    End With
    
    For Each oPar In ActiveDocument.Range.Paragraphs
    If oPar.Range.Characters.First = "<" _  
    And Not InStrRev(oPar.Range.Text, "-") > 0 _
    And Not InStr(oPar.Next.Range.Text, "<tr>") > 0 Then
            oPar.Range.InsertAfter "add"
    End If
  Next
  
  End With
lblb_Exit:
  Set bRng = Nothing
End Sub