So in your config for the Rook40, for the sliencer soundTail for interiors. You have the call for the sound as the following

class SoundTails
{
class TailInterior
{
sound[] = {"A3\Sounds_F\arsenal\weapons\Pistols\Rook40\Silencer_Rook40_tail_interior",1.0,1,400};
frequency = 1;
volume = "interior";
};

However if you look at how the sound file is actually named in sound folder, it's named "Silencer_Rook40_interior"