Can't login to admin

I also have this problem, but I have additional information. The error messages appear to be plugin conflicts. Primarily with All in One WP Security and Firewall when you have selected to rename the login page — To regain login capability, disable (rename) the offending plugin ‘Summits Alert’ and then go back and edit your alert message. If it contains any code, the errors return. Alternately you can deactivate it.