I'm sorry for the inconvenience. Unfortunately I was not able to replicate the error.
It is possible that you are experiencing an error that happen sometimes when you try to teach your Pokémon a move or it try to learn it through level up.
To fix that, could you please try the following procedure and see if it fixes your error:
Delete all the PRO Files that you have (.zip and remaining files too).
After you've downloaded again the latest client, please try to teach again the move to your Pokémon and the issue should be solved.
You can buy another dig in one of the following places: ‣ TM28: Dig -
One time for free in Cerulean House 6 /
Celadon Mart - $3,500 /
Route 36 Smuggler - $5,000 /
Lilycove Mart - $4,000 / FREE Route 114
Please, let me know if you have been able to solve your issue and if you have any further questions.
Have a wonderful day !