May 01, 2012 01:34 PM|hans_v|LINK
string connectString = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=//db.accdb;Persist Security Info=True;";
The Jet.Oledb.4.0 driver doesn't work for access 2007 (.accdb), only for Access 2003 (*.mdb) and below.
So either convert your .accdb file to an .mdb, or use the new ACE 12.0 driver. Note that this driver is NOT installed by default on a Windows server, so it might not be available in you production environment!