W3 crashed my site

After activating this plugin I received the message Fatal error: Call to undefined method stdClass::set_prefix() in /home/content/97/5423497/html/keytagclub.com/wp-includes/load.php on line 337

Ended up renaming the plugins folder to plugins_old, copying it then renamingthe new one plugins. Then deleted W3 Total Cache. After logging back in, still got messages but was told which lines to delete one by one. Works now, but not going to try again.

Side note – using W3TC on 2 other sites with no problems and noticable speed increase. Wish I dared to use it on this one!