When you upload tracks, you can only find default tracks, what?
If you mean save tracks, then check where you are saving them, make sure it is in your tracks folder in NoLimits.
If you have vista you will have to show hidden folders by going into folder options and ticking the box. Then it will be in (Drive)->Users->(YourName)->Appdata(hidden folder)->local->VirtualStore->Programfiles->Nolimits1.6->Tracks
Awesome. That worked. It sucks there's an upload limit though... Anyway I have two tracks up now. A Twisted steel coaster, called Shogun, which was my first track on No Limits, and Lionheart, my first wooden coaster.