Create a Trainer class
You might have already read the PSDK Trainer tutorial and you would like to change the class of your trainer or you got this error,
In that case, follow this tutorial.
Add a Trainer class for a new trainer (to solve the aforementioned error)
Open RubyHost in the Trainers tab:
Edit trainer class
Then, click on
Add text and fill the fields according to your game languages:
Modify a Trainer Class of an existing Trainer
Select the Trainer ID (here it's 127):
Replace the names in the fields according to your game languages:
savefor each modification in order to apply it.