The splines aren't rendering because splines don't render by default. Make sure that enable in viewport and enable in Render are checked. Or just drop an Edit Poly Modifier on top of your spline (good for flipping normal for grooves anyway).
Yep like ghostscape pointed out max defaults to channel 1. You're material is set to use UV channel 1, change your material to 2 (or whatever channel your good UVs are on) and it should display correctly.
Do you have concept art or a screenshot of this somewhere? I don't recall the Quake4 pistol looking like that. Actually I don't recall a pistol in Quake4 at all? I thought your default weapon was an assault rifle?
I bet your photometric light had a shadow map res. That was too small. I think by default they are very low. I usually switch to ray traced shadows anyway, then you don't have to worry about that.
#2 if you go into the properties of the texture in the generic browser, all textures when imported are set to Stream by default, unless you specifically checked NeverStream. generally its best to leave the setting alone but this is how you disable it :)
- try the default lighting (ctrl+L) - chage the texture size of your GFX card,- depending on your hardware - if nothing works go with flat viewport mode (helped me in a very complex project where everything was texturized)
As for the horse, try taking a look at the works of Edweard Muybridge: http://www.digitaljournalist.org/issue0309/lm20.html I have this book and it's great : http://store.doverpublications.com/0486202038.html I would just model the breasts in a default 'at rest' postition.
as far as textures are concerned DPI does not mater, leaving at the default of 72 will be fine. The only thing that matters is size of your image in pixels. so a 1024x1024 image at 72 dpi will be the same texture as 1024x1024 image at 150 dpi.
Using these non-default settings that ott and gamedev mentioned are also much better for your render to texture normal / ao maps as well. The result will be much smoother. I tend to use catmull-rom and then max 2.5 or hammersley..
Delete your Ini file. If that doesn't work, try reverting to default UI. If that doesn't work, try removing your UI stuff (not sure if that will crash max?). You could also try pasting over someone else's.