Error when open the summary

Can anyone tell me what is happening here? I've tried to solve it, but I'm out of ideas. Please, I'll be so glad if someone can help me. Thanks.

I tested right here on Essentials v17.2 with all Rotom forms and there no bug. I had no idea what script you have changed. Even when I removed Rotom cry file, the game doesn't crashed.

Oh, well... The same happens with Giratina, Keldeo, Shaymin, Arceus... and almost all Pokémon that have a form. But, thanks for asnwer me, anyways.

You failed to mention that you are using Custom Scripts like Autosave. Delete them to look if this solves your problem (It is enough to put an =begin and an =end at the very beginning/end to the custom script).