Fixed my issue, which appears to be something to do w/ the plugins.
This worked for me:
1. Using an FTP program (such as FileZilla), I re-named the plugins directory on my site. It is at /wp-content/plugins/ [changed the name of "plugins"]
2. I refreshed the site and rec'd a few errors for files accessed in my wp-content directory [I rec'd errors for advanced-cache.php, db.php and other files] - I noted the file names in the error messages after each refresh and changed the names of those files as well - one at a time after each refresh]
3. I refreshed the site again - no errors and WordPress login loaded. Fixed!
Subsequently, I renamed the plugins directory back to plugins. Then once logged into WP, I visited the plugins and turned them back on one at a time. No issues now.
I hope this helps.