i'm not sure if i messed w/ any settings, but i know that lately when i load a .wav file sample, like a guitar or a jazz sample, and i change the tempo, it asks if i want to stretch the sample or not. if i do, it will change the tempo of the sample to the tempo i want for the whole song. so if you know the tempo of the sample, set that tempo in FL so that everything else is that way.
maybe not the perfect way to do it, but it works for me. hope it helped a little.
to chenge teh tempo there is alittle thing on teh top that says tempo and you can mov ethat up and odwn, if you wann time stretch a sample then stretch it to 1 2 or 4 bars using the option under the sound options