I was testing the Telerik components demos and suddenly got this execption: "Microsoft.Jet.OLEDB.4.0 Provider is not registered on the local machine".
I found that this error can occurs when your Windows is a 64-bits version and Visual Studio is targetting 64-bits (or any CPU which prefer the 64-bits version).
To fix the error, simply change your targeted processor to x86 and everything will work fine!
The solution is simple but the error message is very misleading!