Lotus requires that you be more formal with web addresses. In your case, you will need to use the web address or fix it in your code. e.g.
Sub Test()
  Dim sHL As String
  sHL = Range("B2").Value
  If UCase(Left(sHL, 4)) <> "HTTP" Then sHL = "http://" & sHL
  MsgBox sHL
End Sub
If you are using other addresses that should have the mailto or ftp prefix's, you will need to fix those accordingly.