sengoku-er

So basically I cannot advance past turn 54 for some reason at all. Every time I do I get this error, what's causing it, I've been trying to fix it for the past few hours and I can't go any further now due to it. Does anyone know the issue, it only happens when Shinazu appears https://imgur.com/a/1m3PkGV To give further context: I'm following this guide to the T for turn 54 https://gamefaqs.gamespot.com/pc/936089-sengoku-rance/faqs/58210