It's a low volume beep. If there is any background nosie then it is harder to hear. Maybe try a higher volume level and or adjust background volume nosie (lower background). My test were done on FMP12 Advanced on Windows 7 Pro and I got a sound.
I turned off Pandora and have the volume at max on my laptop and still don't hear a Beep.
I'm a newbie so maybe I have something else set wrong?
Anyone else have an idea?
How are you testing it? Try a new button and assign "beep" solely to that.
Check your control panel for type of Beep you have selected.
I have no idea when this happened but in the Volume Mixer - Speakers dialog System Sounds for Applications was set to muted.