I upgraded my website to Asp.net 4.0 and started getting the following error. Am running Windows 7 with IIS.

The 'Microsoft.Jet.OLEDB.4.0' provider is not registered on the local machine.

My application reads a CSV file using Microsoft Access Database Engine 2010 Redistributable, which you can download from that link.

Since my computer had some 32-bit Office applications, I installed the 32-bit AccessDatabaseEngine.

The error is caused because the Application Pool was not set to allow 32-bit applications to run. This error has nothing to do with Asp.net 4.0 only in that I created a new Application Pool and the default is to not allow 32-bit applications to run.

To allow 32-bit applications to run:

1. Go into IIS Manager
2. Click on Application Pools
3. Right click your application and select Advanced Settings
4. Under General, at the top, for Enable 32-bit Applications set the value to True