FIX: Wordpress / PHP Error: "an error occurred while processing this directive". Debug.log output available

Project is to fix an error in a WordPress site. The error appears to be in a PHP file. The error is very generic and [login to view URL] on some page loads, not others, and when it does, if you refresh a few times, page may [login to view URL], some pages just will not load at all however may times you refresh. The site in question has been running 5 years with no issues like this. I wanted to update it to WPv5.0 (from 4.9.8), so tried running a backup using 2 different WP plugins (such as readybackup), both backups stalled after being left for over an hour, so I just shut them [login to view URL] started after this. Diagnosis/work done so far: Uninstalled the 2 Backup plugins + Disabled ALL plugins - site works fine. Enabled plugins 1-by-1. All are up-to-date including Woocommerce and its database. When WooCommerce activated the error messages appear again: "an error occurred while processing this directive." Ran the Wpress updater to v5.0 - ran ok without Woocommerce activated. Ran update to the Genesis framework theme (Enterprise Pro child theme) to latest version 2.7.1 (Nov 2018 version) - updated ok without Woocommerce activated. Ran a recursive script to check / change all files folder permissions: 0644 for files, 0755 for folders, output=o needed [login to view URL] checked as well - random check of files and folders showed all permissions ok. Re-loaded the default/standard/original .htaccess file for Wordpress. Hit 'save' in permalinks in Wpress dashboard. Activated Woocommerce, used the plugin tools to clear transient cache etc.. in database and re-created default woocomm pages (such as cart etc..) through their tools menu. (all the while getting same error in between trying each function and refreshing webpage several times to get it to work). Enabled debug log in wp-config.php. Log output (line after line, of the SAME error only): [11-Dec-2018 02:03:10 UTC] PHP Warning: mysqli_query(): (HY000/2013): Lost connection to MySQL server during query in /home1/alphxxxx/public_html/turbochargerxxxxx/wp-includes/[login to view URL] on line 1924 MY NOTE: xxxx = hidden info. Other Errors found: In folder: wp-content/uploads/ File: wc-logs 2018-12-10T08:11:02+00:00 CRITICAL Class 'WP_Roles' not found in /home1/alphabo3/public_html/turboxxxxxxxxx/[login to view URL] on line 400 And below, an error that repeats itself, found in the same file as above: 2018-12-10T10:48:21+00:00 CRITICAL Uncaught exception 'UnexpectedValueException' with message 'RecursiveDirectoryIterator::__construct(/home1/alphxxxx/public_html/turboxxxxxx/wp-content/wp-performance-score-booster): failed to open dir: No such file or directory' in /home1/alphxxxx/public_html/turboxxxxxx/wp-content/plugins/wp-performance-score-booster/[login to view URL] Stack trace: 0 /home1/alphxxx/public_html/turboxxxxxxxx/wp-content/plugins/wp-performance-score-booster/[login to view URL](15): RecursiveDirectoryIterator->__construct('/home1/alpxxxx...', 4096) 1 /home1/alphxxxxx/public_html/turboxxxxxxx/wp-content/plugins/wp-performance-score-booster/[login to view URL](12): delete_storage_dir('/home1/alphxxx...') 2 /home1/alphxxxx/public_html/turboxxxxxxx/wp-admin/includes/[login to view URL](1018): include('/home1/alphxxxx...') 3 /home1/alphxxxxx/public_html/turboxxxxxxxxx/wp-admin/includes/[login to view URL](831): uninstall_plugin('wp-performance-...') 4 /home1/alpxxxx/public_html/turboxxxxxxxx/wp-admin/includes/[login to view URL] YOU MUST: 1) Be an expert in php 2) Be VERY TRUSTWORTHY and RELIABLE 3) Be very savvy with Wordpress 4) MUST complete the entire fix to my satisfaction in 48 hours after being awarded the job. 5) Have read the ENTIRE proposal and Error logs and ALREADY know what needs to be fixed or a very good idea on how it will be fixed. THIS IS A REQUIREMENT TO POSTING A PROPOSAL QUOTE to show you have read it and AGREED: Please write in the first line of the quote: "Hi James, I have read your Project completely, and I agree to the above 5 terms." Thanks.