TTT Custom Sounds problem

Hey, so I’m currently trying to add a custom sound to my TTT server for playing via the ulx playsound command.

However, I’m having a fair bit of trouble with it.

I’ve added the sound as a wav to /gamemodes/terrortown/content/sound/ttt
on both the server files and the FastDL server, and the download is working (the file is downloading for people who join).

Furthermore, I’ve added:

to the lua file “forcedl.lua” in my server’s autorun folder.

However, when I try to play the sound, I get:

[LC ULib ERROR] Received invalid sound
You played sound ttt/solgryn.wav

And obviously, the sound doesn’t play.
Any help would be MASSIVE appreciated, as I have to go away for the weekend and would like it done before then. Cheers!

[editline]15th February 2013[/editline]

Ok, there’s like, 17 people looking at this thread.

Someone must know.
Someone must at least have a suggestion.