When I upgrade the plugin to 5.1.2 and activate, this message occurs:
[error] 27861#0: *36465 FastCGI sent in stderr: "PHP Fatal error: Class 'w3v_Controller_Action_Action' not found in wordpress/wp-content/plugins/blog-linkit/library/wordpress/Controllers/ActionController.php on line 3"
http://wordpress.org/extend/plugins/blog-linkit/
How did you upgrade?
Through WordPress' own update or by downloading it and uploading yourself?
If you did it manually, you need to delete the old version as stated in the instructions, as the file in questions is a file from a previous version that is no longer in the new version, and referes to things that do not exist in the new version either.
If you used the automated update, I would have expected it to remove any only files first, but maybe it doesn't.
-D
That did the trick ;-) Tnx!