Where to download the plugin while using Cinema 4D Lite

Arnold Render is a commercial third-party renderer and IGES import is part of the commercial Studio version of C4D. Whoever provided the file needs to strip the renderer info and convert the geometry to native C4D objects. Otherwise this is no use to anyone. In fact it would even be problematic for other pro C4D users who may have Studio, but not Arnold Render. In the end the effort required to even get this working may not at all be worth the time.

Mylenium

I think you can not open this file with the Lite version included in AE. The Lite version is R19 but Maxon added support for IGES data in R20. Arnold can be downloaded from solidangle.com, but you will need to create an Autodesk Account and of course it will include watermark for your renders. What you can do is to suscribe to the new R21 version of Cinema 4D and Arnold for one month to finish your project.

Moving to the After Effect forum from Get Started