If this is redundant to the 'Unable to run first scan' post , feel free to delete it.
I installed Wordfence on one of my sites with no problem. Loved it!
I then installed Wordfence on my main domain, but now the first domain doesn't work.
Won't scan, no new options can be saved. Just none of the buttons work. I've tried re-installing to no avail. The settings/plugins/permissions for the two sites are identical as far as I can tell.