I’ve been doing a little work on a WCF service that reads an Excel file. My development machine is running Windows 7 64bit and my service was deployed to IIS. I kept running into a problem with opening the OleDb connection to the Excel file: “Error: Microsoft.Jet.OLEDB.4.0' provider is not registered on the local machine.”
Turns out that Office Jet provider will only run in 32bit. After changing my ASP.NET processes to run in 32bit everything ran just fine.
This KB article shows how to change ASP.NET to 32bit: http://support.microsoft.com/kb/894435/en-us