Thank you both!
I located the wp-config.php, copied, pasted, and updated the file to change the autosave interval with a successful file transfer and update.
Logged out of my WordPress site, logged back in and the error still exists.
Anything else you guys would recommend? Would site backup before updating to 3.9.1 have an effect?
I've looked through the troubleshooting forums, there are others who have experienced the same issue with no resolution, though I know each site is unique. Thanks again for your help!