Did you get this resolved? I need to do something similar but am getting the same error. I had the code working on an xp machine running ss 2005 but...

Try one of these:

SELECT * into #tbltemp FROM OPENDATASOURCE('Microsoft.ACE.OLEDB.12.0', 'Data Source="C:\CFF.accdb";')...[T_prodotti]

or

SELECT * into #tbltemp FROM OPENDATASOURCE('Microsoft.ACE.OLEDB.12.0', 'Data Source="C:\CFF.accdb";User ID=Admin;Password=; ')...[T_prodotti]