-Delete ALL War horn files of this mod.
-Delete the events.idx and SFX.idx in dlv_ext/data/sounds.
-Click on "adapt_sound_nonenglish" or "adapt_sound_english" in \mtw2\mods\DLV_ext.
-(Delete the events.idx and SFX.idx in dlv_ext/data/sounds if they are come back)
-Unrar the "new war horn sounds" folder on your desktop.
-Take the 3 folders inside and put them in mtw2\mods\DLV_ext\data.
When I was "modding" I had this problem because I made a mistake. I don't remember this mistake but I'm sure with this instruction above, you game will works fine. (PS: new version without the folder "new war horns)