Make sure that you put your avatar file into the "avatar" folder (the same folder, where sample avatar is stored).
Got further. I guess i need to get rid of some of the spring bones since it says
reached a limit of maximum spring bone chains
fish: Job 1, './vtuber_webcam' terminated by signal SIGSEGV (Address boundary error)
Yep. There are some limitations with spring bones. I'm working on the improvements of the spring bones.