Inventor View 2016 error "Library... does not exist"

Background

Meridian PowerUser supports integration with 32-bit and 64-bit third-party viewers that are ActiveX controls such as Autodesk Inventor View.

Description

After installing Inventor View 2016 on a 64-bit computer, the viewer works as expected in the 64-bit PowerUser but this error can occur and refer to FWSrv.dll in the 32-bit PowerUser on the same computer. Inventor View 2016 works as expected outside PowerUser.

This is a known problem that was introduced in Inventor View 2015 and is also described with an incomplete solution in Inventor View fails in PowerUser.