I must start to ask if you have Windows Vista...
I have the samething, at least i think so... try to search after a trackfile that you know exists. Probably it will show up under a strange folder named "Appdata". Witch seem to be like a fast access folder for Vista. Vista saves the track there, probably because it doesn't allow changes to be made in a program folder, without having to ask you all the time. in the word change it's included; new files to be created. If you would install No limits under the folder "Users" instead, i think you would have no problems of this kind.
I would suggest, if you not have that many tracks yet, to reinstall No Limits into the Users folder or at least somehow have your tracks folder there, I mean under My Documents.
I have to find my files in this strange folder manually and copy it to my No limits library, it's crap!!!!
hope it helps...