I just upgraded from 2.1 to 2.7. After modifying line 753 of the LoginLdap/Controller.php file to call force_ssl instead of force_ssl_login, I now am presented with this error message. I tried the update through the browser first and got this error. I then tried rolling back my VM and doing the update through the command line and got to this same point. It is the only message on the screen and the HTTP status code is 200. What can I do to fix this? Currently, the entire site is unusable.
I solved the problem by copying out my config file, removing everything from the piwik directory, and then downloading and extracting the latest version. Copied the config file back in, changed all permissions and it appears to be working.