[Ownkruid]

public OnMapStart() 
{ 
    AddFileToDownloadsTable("misc/lastct.mp3"); 
    PrecacheSoundAny("misc/lastct.mp3");
}

Should be

public OnMapStart() 
{ 
    AddFileToDownloadsTable("sound/misc/lastct.mp3"); 
    PrecacheSoundAny("sound/misc/lastct.mp3");
}