Well for one thing you don't seem to have included the environment file in your zip so I can't tell if theres anything wrong with that.
Of the two graphic files in the zip (which I assume are part of the environment) one of them (stars.jpg) seems to be a bitmap file with the wrong extension (should be named stars.bmp). Thats probably the cause of your trouble. As far as I remember NL doesn't support .bmps so you will need to convert it to .jpg.
Location: California, USA Steam:sleaklight Offline
please post this kind of stuff over at coaster candy. your current one does not have all the files necessary so I will delete it right now. FOr that kind of stuff just use coastercandy.com for real tracks use this site.
WWS