mp3 file problem

We are trying to load as an event a sound file that is an mp3, Our first problem is that we keep getting a message that says the stimulus file failed to load. This happens whether we try sound, audio or movie. We are on a mac, running superlab 4.0.4.
Second, if we could get it running, is there any way to get the audio to pause but not the other events and then have the audio resume after a certain time? It is intended as background stimulus for the visual event but we need pauses during which the subject responds (on paper). Anybody got any ideas?

On the Mac, both the “Sound” event and the “Movie” event always go straight through QuickTime. The “Audio” event reverts to QuickTime for files that aren’t either WAV or AIFF. Therefore, a failure to load this file ultimately implies that QuickTime can’t open the file.

The only exception to this that I know of would be if the file doesn’t actually have the “.mp3” extension at the end, as SuperLab can easily get confused about the file type without the extension.