MICROSOFT.ACE.OLEDB.1.2.0 PROVIDER IS NOT REGISTERED ON THE LOCAL MACHINE‏

I've had the exact same problem In my Dot Net web application . This issue comes when you are running 64-bit Windows and Microsoft has not written MS Access drivers for  64-bit Windows in Office 2007, the good news is that in this issue has been fixed in  Office 2010, However; if you are running Office 2007 on 64 bit Windows you need to resolved this issue by your own.

What you need to do to get around this issue is you need to download patch which is available at the following location:

http://www.microsoft.com/downloads/en/confirmation.aspx?familyId=7554f536-8c28-4598-9b72-ef94e038c891&displayLang=en

Install it and hopefully issue gonna get resolved.

Reference: http://social.msdn.microsoft.com/Forums/eu/vsto/thread/43d6b544-7172-4fe7-babf-a541e5f6a1c9