I am really sorry for the delay of this reply as it is a weekend for us here.
I've tried in my locally, but it seems like I can't reproduce this error, can you provide us with your Joomla backend and FTP access so we can better have a look?
Just login to site in Joomla from my home computer I run windows 8.1 and it open SEO no problem (pic1) in office I have HP workstation z840 also windows 8.1 and I try 20 times there still error... can it be because computer? or maybe cookies?