500 error after upgrade

Support & Bugs
1

Tried the “The One-Click Piwik Update” (which has always worked well in the past) to 2.6.1.
After update, I received a 500 error.

Tried the manual update to 2.7.0-b3 and have the same 500 error:

Fatal error: Class ‘Piwik\Plugin\ControllerAdmin’ not found in local-path-to-website/piwik/core/dispatch.php on line 16

Not being terribly familar with piwik’s files, I’m a little lost on where to go from here.

Here’s some server info if needed:
Platform Type Debian
MySQL Version 5.5.32
Perl Version 5.8.8
PHP Version 5.3

Thanks,

Rush

2

If you refresh the page does it work? Maybe restart the webserver (sometimes useful to clear php caches)?

3

Unfortunately, I’m unable to restart the server, it’s shared hosting.
Refreshing the page yeilds the same results.

Thanks,

Rush