Strange problem: Don't have Permission to do that, and something else

Just out of the blue (as in I haven’t added any new plug ins or done anything new to the site in weeks), I go to add a page, and I get a “You don’t have permission to do that” error. I also get the same thing when trying to upload a PDF.

Then, I decide to go to “Settings” – “General”.

I notice a misspelling in the Tagline field. I correct and click save, and it takes me to a strange page where I see a long list of variables, starting at top with:

All Settings
active_plugins: serialized data
add_plustax 0
admin_email (my email)
advanced edit: 0
aioseop options: serialized data

and so on, a long list.

Ideas??