From Glitch City Laboratories
An error handler "ERROR!", used to refer to an unused party menu function with a hexadecimal identifier 15 (21); an identifier straight after the last valid option "MAIL".
This article is about an error handler which is used for an invalid party menu option within Pokémon Gold, Pokémon Silver and Pokémon Crystal. For faults and errors in the Pokémon game franchise, see glitch.
The dialogue string 'ERROR!', exists in the second generation of Pokémon games. It is internally used by the game as an error handler, to refer to an invalid party menu option of hexadecimal identifier 15 (21).
For unknown reasons, the string 'ERROR!' is only used by the game to denote one invalid identifier. This may suggest however, that the dialogue string also acts as a placeholder, to portray that datum for the names of 'field moves' which are read past this identifier are not valid; instead, they take their names from translated information from other parts of the game's RAM.
The player can enter the GameShark code 0115D6D0 to replace the third party menu option with the 'field move' "ERROR!". Functionally, because of how the game's RAM is structured, "ERROR!", acts as the "CANCEL" option and simply takes the player back to the initial party screen.
- PAY DAY (field move)
-  - "The Cutting Room Floor": Alpha/Beta elements present within the final release of Pokémon Gold and Silver.