Are you using renewal or the old ones?
Are you sure using the correct path?
\data\sprite\¾ÆÀÌÅÛ\Helmet.spr \data\sprite\¾ÆÀÌÅÛ\Helmet.act \data\texture\À¯ÀúÀÎÅÍÆäÀ̽º\item\Helmet.bmp \data\texture\À¯ÀúÀÎÅÍÆäÀ̽º\collection\Helmet.bmp
or maybe this
ACCESSORY_LARGE_RED_WING = 873,
You must compile to lub if you leave space between IDs, if you don't plan on compiling to lub, make sure you do not skip any numbers.