Showing error while using losetup in ubuntu 18.04

sudo losetup /dev/loop0 floppy.img

I am using this command in my bash file. actually, I am trying to build a tiny Operating System.

Error Message:

losetup: floppy.img: failed to set up loop device: No such file or directory

my .bashrc $PATH

export PATH=$PATH:"/usr/local/sbin/"export PATH="$PATH:/sbin/"export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"