[stepk]

Thanks for the screenshots. I took some on my own, so I can show you and others how to go about this kind of issue. First of all, when KUAL displays a black disc in its sub-menu title and/or in the breadcrumb line that's a sign of attention. With reference to the screenshots below, I placed just the backdoorlock folder in /mnt/us/extensions and started KUAL, and got a black eye, I mean, disc (shot #1).
Click the KUAL sub-menu and get further details. Click the syntax button (#2) and see message "More info in KUAL.log" (#3).
Now, this message should appear in the breadcrumb line (screen top) but instead it appears in the status line (screen bottom) where it's less visible. It's a bug, I will fix it and place the message back in the breadcrumb line.
You want to see the log file, so click "Save and reset KUAL log" (#4) then quit KUAL and scroll to the document named KUAL-20yy-mm-etc. and open it. Mine's shown in #5.
This is where it can get too technical for some people, but bear with me. That message means something's wrong with file /mnt/us/extensions/menu.json. You need to fix that file. (The actual file path will change depending on the contents of your extensions folder.) Open the file in your favorite editor, and find the spot where KUAL thinks there's an error. In this example KUAL's saying the it was expecting a value (like a string or a number) but found a closed square bracket instead. It also shows you where that happened, in this case the offending square bracket follows "bin/move.sh" } , Mmm... that dangling comma doesn't look right. Delete it (the comma), save menu.json and restart KAUL.
Now the extension shows up! (#6)