That’s because you are supposed to be using 127.0.0.0, not a 192.168.n.n number. 192.168.n.n is addresses on your local network. 127.0.0.0 is the dev/null ‘bit bucket’.
Re FF addons to disable Javascript, I like SettingSanity. Not only does it let you disable Javascript (which I rarely bother doing), but it ALSO restores the “Advanced Javascript Settings” options which also vanished when the option to disable Javascript went away. I have always kept the “Allow scripts to: Disable or Replace context menus” option turned off (which stops JS programs from intercepting your right mouse button).
OOPS! I mis-remembered when I wrote that. Upon checking my hosts file:
I AM using 127.0.0.1 (not 127.0.0.0 and not 192.168.anything).
(192.168.0.1 is actually my router, come to think of it.)
Anyway, the result is as I described. 127.0.0.1 gets directed to my own server, which says, e.g.:
Not sure if 127.0.0.0 will make any difference. I’ll give that a try. It’s okay either way – these error messages don’t bother me, they don’t show any distracting graphics or animations, they don’t contain insulting shit about me being the 100,000th lucky user, none of that.