Sorry but I woke up this morning, and the file in the private area had started producing a 500 error.
I first tried it on a different browser. No luck.
So then I completely deleted all the five files SecurityAssist creates. I rebuilt and then uploaded the new versions.
Still not working.
Next I deleted the _mmServerScript folders on both the local and the remote servers.
Still not fixed.
(I also tested the connections in DreamWeaver, and they are working OK, but did not rebuild the _mmServerScript folder).
I did try a variety of MySQLi queries last night to try to build my intended switch page, but as far as I recollect, everything was working before I went to bed.
But the only pages that seem to not be working are the Security assist ones.
[I restarted DW and tested servers. This time it rebuilt the _mmSS folders, so I uploaded the new build to the server).