filipelou,
The fact that the tempo was set at 100 doesn't mean that is the BPM of the file you are trying to create.
To test, set any device with a metronom at 100 and play wiht your wave file to see it it matches.
The best way to record an audio drum from scratch is have the player wear headphones with a metronom click set at BMP=100. Play for about 24 measures so you get the best 'feel' - then cut the wave up to the desired length.
Thanks,
AJ