ingp2nsvf.py doesn't work

[Seagullflysxt]

Hi, I take photos around a single object in real scene,and I then I remove all the backgrounds make them transparant, and then I use colmap to get the relative params,and then I use scripts in instant-ngp which is "colmap2nerf.py" to get the transforms_*.json files,I think the dataset I made might be the type of blender dataset？
Anyway ,when I start to train,It says :

Then I think maybe I should use the ingp2nsvf.py to convert dataset to nsvf type though my data don't have background.
So I tried the script ypu provide, but it says no json file spotted:

my dataset is organized as follow: