I'm back to thinking it's something with the .NET samples. I just tried the normal Horde3D samples, and they seem to be working perfectly well for me.
The trouble is that I'm not sure
why it's the .NET samples. I've been looking around, trying to find whether there's some texture path set wrong, or anything like that, but it kind of looks like the material paths are determined by an XML file, which is the same for both the .NET and the normal samples.
I know this is a stupid issue and no doubt has an easy fix, but I'm not really sure where to start looking. I've been teaching myself to program for the last couple of months, and I've made huge improvements, but even though I'm to a point where I can more or less understand the code I'm reading, I don't have much experience with large scale software, or familiarizing myself with the structure of another developer's code, or the "nitty gritty" details of Visual Studio's projects/solutions, properties, resources, or build system -- all the things I think I would need to be able to figure out what's going wrong.
So if anyone has any thoughts . . . I'd really appreciate it! Oh, and now that I've figured out FRAPS was my problem, I can take screenshots using ATI Tray Tools. The first two are the .NET versions, and the last one is the standard Chicago sample just to show that it seems to be working fine for me.
(Broken though it is, the Knight sample looks ridiculously awesome like this -- I actually think I prefer the accidental stylization of my broken .NET version to the original!)