'Original
'oDataMedium.FileName = oFolder & "\" & oFileName & ".pdf"
'Uprava
Dim pdfFullFileName As String = oFolder & "\" & oFileName & ".pdf"
If System.IO.File.Exists(pdfFullFileName) Then
    Try
        'Delete existing file
        System.IO.File.Delete(pdfFullFileName)
    Catch ex As Exception
        'Handle error
        'Show message
        MsgBox(ex.Message)
        'Exit rule
        return
        
    End Try
End If
oDataMedium.FileName = pdfFullFileName