Error when save game

[OtameganeMinh]

I'm working on a Vietnamese version build using your port. Everything plays smoothly in arc 1. But after that (after Sayori hangs and Natsuki & Yuri are fighting), when i try to save, this error keeps popping up and the game won't save.

I hope you can solve this problem. Looking forward to your answer. Thank you very much.
Here's the fork that i'm working
https://github.com/OtameganeMinh/ddlc-android