Excel dll for Microsoft.Office.Interop.Excel

We want to use Microsoft.Office.Interop.Excel in our web application. Everything works fine on our local machines, but on our test machine we're running into problems. It has neither Visual Studio nor Office installed on it.
We're using .NET framework 2.0 and the server is running on Windows Server 2003 with IIS6.

Is there a dll that needs to be installed on the machine or added to the bin of the web application?

Do I need to have Office installed to use Microsoft Office Interop Excel DLL?

Yes, you are right. You need Excel to be installed to use the Excel Manipulation feature with Microsoft. Office.

You will need to have MS Office and the Office Interop assemblies installed on your server in order for that to work.

I'm pretty sure that you will need to have Office installed on the machine it's runnnig on. At least that's my experience from building desktop apps that uses Office.Interop