can’t find options.php on ver 2.8

I’ve been trying to save changes to my site – https://justfr0nd.com – because I’m going ‘live’ now and would like search engines to be able to find me.

But when I click on the ‘save changes’ button under Admin/Privacy… the response is

“Not Found
You are looking for something that isn’t here” on my website.

I’ve tried disabling the sociable plugin as suggested here but it still doesn’t work.

would appreciate any and all help!

??