https://gist.github.com/P3rf3ctXZer0/b2fb4690f9c03a6bbe69a313b3db97b9

This error seems to come from the StructPro mod. Since it is a mod about buildings and schematics, I don't see how this could come from FTGU

Try asking questions help from ternsip https://minecraft.curseforge.com/projects/structpro-mod-fast-schematic-spawning-system you will need to pm him.