I am back again with yet another problem!

Last night, I installed Justin Cornell's BNSF and Southern GP38-2's. When I try to add them to a consist in the scenario editor, their names appear on the locomotive list, but when I click on them, they do not load/ show up on the track. I have no such problems with other locomotives.
Also, after installing the GP38-2's, the default SD40-2 and GEVO (I haven't tried the F7) now emit a thick, black, pixelated smoke. After doing some searching in the "Particles" sections of my assets/kuju/railsimulator and assets/kuju/railsimulatorUS folders, it appears that the following files were modified after the installation:
Engine_DieselExhaust02.bin
Engine_DieselExhaust02 (XML Document)
ParticleGizmo.GeoPcDx
TestSmoke.TgPcDx
and within the particles/textures folder:
Gizmo_noaplha.TgPcDx
I was wondering how I might go about fixing these two problems... One thing that I have learned for sure is to make back-ups before installing new things.
Thanks in advance for any help - sorry that I'm only ever asking for help around here. I hope to be able to start doing some repaints/ screenshot posting in the near future!