Windows7, ISS7, Classic ASP with Access .mdb; Error in recordset .addnew statement

I would appreciate if you could guide me with this problem. I am retouching an ASP application that until now works in XP environment to work in W7 environment. There are no problems to connect and open recordsets in reading to the BD ACCESS (.md) in reading, but in the case of writing recordsets it gives problems in the own instruction ".addnew".

The code is as follows

'Codigo en fichero "cBD.asp"
'---------------------------- 
 .....

 Set mConn=Server.CreateObject("ADODB.Connection")

 mConn.ConnectionString="PROVIDER=MICROSOFT.ACE.OLEDB.12.0;DATA SOURCE=MiBD.mdb"
 mConn.Mode=adModeReadWrite
 mConn.Open
...

'Codigo en fechero "pagina.asp"
--------------------------------
...
<SCRIPT language=vbscript RUNAT="SERVER" SRC="inc/cBD.asp"></SCRIPT>
...
<%
  set oBD = new cBD
  oBD.OpenConnection 
  'Abro el rs sin problemas
  oBD.OpenRecordSet "MiNombreDeRS",adOpenStatic,adLockOptimistic, "MiNomTabla"
  'Pero esta me da error
  oBD.rs("MiNombreDeRS").addnew

To get to where I am, I had to change the old JET connection to the ACE so that the readings can be made. In case of problems of (32-64Bits) configuration, I have also tried to run both the "AccesDataBaseEngine.exe / passive" and the "AccesDataBaseEngine_X64.exe / passive" but without success.