I followed all of the steps as described in the OP, copied the 2 files (I tried both versions in the zip, odd that the instructions never address the fact that the zip contains 2 versions of the files in the system/ and system/bin directories in the zip) and installed a terminal program. I set the system directory back to read only, and ran the commands as directed. The terminal program correctly got superuser access, but when I run the superfreeze command, all I get is:
superfreeze: permission denied
For reference, I am using Calkulin's 2.91.
What am I doing wrong?