Your image at the link you provided loads VERY slow even on my fast internet connection. It must be a VERY large file. It shows a RUNME.done, which shows that the RUNME.sh did run (one time). You must delete that RUNME.done file to run that or a different RUNME.sh file again.
Your screenshot image does NOT show the contents of the RUNME.sh file. If it is the DEMO script it will just display the pattern and text if it runs again. Please put the RUNME.sh that does what you WANT on your kindle and delete the RUNME.done file, then reboot.
If it does not work, then please show the contents of the script you WANT to run in a post here. It appears that you have only run the wrong RUNME.sh file, but not the correct one that makes your intended screensaver changes.