Yes, it was InstallShield. Good to know about those underscore file extensions. This is the first time I've run into the situation, but have always wondered why certain installation media had those underscores.
What was curious was that the Cyrix 5x86 was able to use the Direct3D functionality of the 4.11.6263 driver, while the AMD 5x86 was not. If anyone else is looking to run an ATI Rage128 VR with the AMD Am5x86 and tinker around with OpenGL and Direct3D games, the above noted solution is for you. I had to test around a dozen driver versions.
I am having a similar problem with the GeForce2 MX400. While I can get OpenGL working with the Am5x86 using Detonator 12.41, Direct3D will not function with this CPU. A Pentium Overdrive was required for D3D. The Windows display driver would not even function with a Cyrix 5x86. I've tried NVIDIA drivers 6.5 and onward, but could not find functioning D3D drivers. I did attempt some version 2, 3, and 5's from NVIDIA, but they did not support my MX400. For your curiousity, the Am5x86-160 could play GLQuake with sound enabled at 1280x1024 with 26 fps in timedemo 1. The POD-100 scored 36 fps on the same system. Due to the lack of functioning D3D drivers for the Am5x86 on the GF2 card, I have decided to use the ATI Rage 128 VR in this system, which is a lot slower in GLQuake, but allows for D3D games like Outlaws, MDK, Battlezone, etc. I've also considered just running the POD-100 in this system with the GF2, but then it wouldn't be a 486 any longer.
Plan your life wisely, you'll be dead before you know it.