2.) Allowed ALICE to analyze logs, attached, and attempted all listed troubleshooting suggestions EXCEPT excluding large video file, which I want to backup and have been backing up.
3.) unable to exclude any database tables due to another AJAX Error, see attached screen capture.
4.) each time backup was attempted it failed, and the connection to the server was reset, requiring approx. 60-90 sec. timeout before being able to reestablish contact w/Akeeba Pro and Joomla Admin pages -- see attached screen capture.
5.) I tried different Windows browsers -- Safari, Chrome, and Firefox, as well as iOS Safari -- all failed to complete a backup or system restore point, throwing a "Backup Failed" error and connection reset each time.
6.) I tried all suggested permutations of min/max execution times and execution time bias in configuration -- no difference.
7.) I tried adjusting part sizes in the JPA Archiver settings -- no difference. I used multiple networks and multiple computers at multiple physical locations -- no difference. I tried turning windows firewall on/off -- no difference.
8.) I tried every idea I could find in every thread at Akeeba that seemed related to my problem -- no difference.
9.) I was ready to uninstall and reinstall, and then decided to reach out for assistance first.
10.) my last successful backup was on 15 July 2014, and this problem has not occurred even intermittently before 19 July 2014.