Yet Another wp-content Problem

I think I have read every forum posting on this issue, 3rd party solutions, lines o’ code, php patches, etc. out there on the Interwebs, and I’m about to tear out what remains of my hair. We chose WP as a content management system because of its relatively intuitive user interface; frankly, my brain is not wired for trying to decipher the hieroglyphics that underpin WordPress, and solutions that say “simply paste these lines of code…” then cause the site to go even wackier are as useless as instructions on learning Chinese as posted in Urdu on a Russian website.

Now that I have vented…

Only recently, attempts to update plugins via the Dashboard have resulted in the all-too-familiar:
Unable to locate WordPress Content directory (wp-content).

Likewise, existing posts offer visitors this delightfully good reading: Catchable fatal error: Object of class WP_Error could not be converted to string in /home/xxxxxx/public_html/wp-content/themes/responsive/core/includes/functions-extentions.php on line 123. Needless to say (but I’ll say it), the xxxxxx string is a placeholder.

Clearly E.T. doesn’t know how to phone home re: wp-content

Meanwhile, the Form Maker plugin was apparently causing other grief as evinced by this which disappears when the plugin is disabled:

Warning: Unknown: open(/tmp/sess_9776d44083d054f9a10d94f679df44db, O_RDWR) failed: No space left on device (28) in Unknown on line 0

Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/home/xxxxxx/public_html/wp-content/plugins/form-maker/session) in Unknown on line 0

Great! Except now the Contact Us form is tango uniform.

“Simple,” you say? I think I just lost a filling trying to figure this out…