Hello, ydbn!

Change target processor, in the VS these settings are under following path

Project->Properties->Build->Platform Target. Select x32

HTH

--
With best regards, Vadym Stetsiak.
Blog: http://vadmyst.blogspot.com

You wrote  on Thu, 6 Sep 2007 10:54:04 -0700:

y> I have a C# program using DAO:

y> DAO.DBEngine dbEngine = new DAO.DBEngine();
y> DAO.Workspace workspace = dbEngine.Workspaces[0];
y> DAO.Database db = workspace.OpenDatabase(excelFileName, false, true,
y> "Excel
y> 8.0")

y> I works well until we upgrade Windows Server 2003 to 64 bit. I got
y> the  following error:

y> Unhandled Exception: System.Runtime.InteropServices.COMException
y> (0x80040154): Retrieving the COM class factory for component with
y> CLSID  {00000100-0000-0010-8000-00AA006D2EA4} failed due to the
y> following error:
y> 80040154.
y>    at ExcelTabs.Program.Main(String[] args)

y> How to force the program run in 32 bit mode?