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

This is one of the most common errors that occurs with IIS 7.

Solution:

To use the UI:

• Open IIS Manager.
• In the Connections pane, expand the server node and click Application Pools.
• On the Application Pools page, select the application pool that contains the application that you want to change.
• In the Actions pane, click Advanced Settings...
  
• In the Advanced Settings dialog box, enable option "Enable 32-Bit Applications" and then click OK.
  

Command Line:

To change the application pool in which an application runs, use the following syntax:

%windir%\system32\inetsrv\appcmd.exe set config -section:applicationPools -[name='DefaultAppPool'].enable32BitAppOnWin64:true