I believe you are reading the code incorrectly. There are essentially 11 codes (box names) that need to be entered for the ace to work and some of the box names are different depending on the item you are trying to generate. For example, if you are trying to generate a master ball (hex 0001) the box 5 name would be G … … o _ _(the underlines are spaces). Note that this box only uses 6 characters not the full 8. Use this URL to find the index of the item you want
https://m.bulbapedia.bulbagarden.net/wiki/List_of_items_by_index_number_in_Generation_III
FYI Papa Jefé has some great videos on youtube for fire red ace