[SCRIPT] Sound File isn't working?

[MissMarilynn]

void ClockScare(string &in asParent, string &in asChild, int alState)
{
PlaySoundAtEntity("explosion", "explosion_rock_large.snt", "clock_grandfather_1", 0, false);
PlaySoundAtEntity("", "react_scare", "Player", 0, false);
StartScreenShake(1, 1.0f, 0.5f, 5.0f);
GiveSanityDamage(5.0f, true);
}

Everything else works except the sound. :/

Just to check: What is suppose to go in the clock_grandfather_1 space? I put an entity...is it suppose to be an area?