Anyone else get this problem?

I download, modified it (with audacity) and add an .mp3 file to alice, but when i run the method with the sound, say i gunshot, the sound is about 0.15 seconds long and the sound plays at random locations of the sound. Sometimes it plays the full sound, sometimes it plays from the middle of the sound, and sometimes you don't even hear it. I'm running Alice 2.2 on a school computer, can any of you guys help out?