This is throwing an error since 7.3 went live.
I looked the error up and found this thread:
https://us.battle.net/forums/en/wow/topic/20758856637
Another search found me this thread which shows which number to use:
http://www.wowinterface.com/forums/showpost.php?p=324045&postcount=7

So I've changed line 73 to:
PlaySound(856)
It works like it used to then.

https://www.townlong-yak.com/framexml/live/SoundKitConstants.lua
^ List of them all if you're interested.

Cheers, that is interesting although I don't know enough to use it.
"Just enough to be dangerous, not enough to be really helpful." ;-)