Unable to Write ETACS...

[stecoop01]

I am trying to change the setting for the Power Window Key-OFF timer from 30 seconds to 600 seconds. In the first image you can see how I'm connected:

Clipboard-1.jpg (61.67 KiB) Viewed 259 times

In the next image, I have selected the 600 second option:

Clipboard-2.jpg (132.51 KiB) Viewed 259 times

I Click "Apply"; I then click "Write Custom" and this is what happens:

Clipboard-3.jpg (86.38 KiB) Viewed 259 times

What am I doing wrong?
I've tried 3 times with the same result.