Script 'PokeBattle_Trainer' line 98: NameError Occured

I just spent a very long time creating a game in RPG Maker XP with the latest Pokemon Essentials pack, but when I tried to play it, I got a message saying

"Script: 'PokeBattle_Trainer' line 98: NameError Occured
uninitialized constant PokeBattle_Trainer:: PBSpecies"

and then the game crashes.

How do I fix this problem?

You need to compile the data first, I believe. Hold Ctrl while starting the game in playtest mode.

It's happening the same to me... Any idea?

Take a look at these rules before you continue to post. You just revived a thread that is almost 3 years old while the limit is only 2 months.