Well... I found a couple tables and options. I deleted every one. Installed the plugin. Activate, OK. Gone to the settings page: blank. Browse to any other page: blank. Renamed the plugin to force deactivation, deleted files, deleted tables and options. :(
I found two PHP errorlogs created in root and wp-admin folder at the same time the plugin was activated.
Both files weigh 14 MB and shows basically two MySQL errors due to very large queries taking place, both them consisting in
[29-May-2014 15:56:19 UTC] Error MySQL server has gone away de la base de datos de WordPress para la consulta REPLACE INTO cu2vn4ah_wsal_metadata (id,occurrence_id,name,value) VALUES (...............WSAL_DB_ActiveRecord->Save
I cannot post the entire queries since they are extremely large and exposing lots of strings from the site.
The error log at root folder ended with:
[29-May-2014 15:56:20 UTC] PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 46847281 bytes) in /home/marcelop/public_html/blog/wp-includes/wp-db.php on line 1033
[29-May-2014 15:56:20 UTC] PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 46868933 bytes) in /home/marcelop/public_html/blog/wp-includes/wp-db.php on line 1033
which is odd since the server allows for 128 MB max mem for PHP.
After this, I installed the plugin in a test site and it all gone just fine. No troubles. No errorlogs. Same server. Same configs.
Maybe there are more options to look for?
Maybe the plugin is conflicting with MySQL 5.6?
Maybe the plugin is confused by the WP db prefix?
From what I can tell, this website won't be able to run the plugin. Others will do. But not this one.
If you happen to have any idea, you're welcome :)