Hi, I had this issue as well and resolved it by the following:
In wp-content/plugins/wp-preloader/wp-preloader.php line 9, change
do_action( ‘plugins_loaded’, ‘wp_preloader_load’, 25 );
to
add_action( ‘plugins_loaded’, ‘wp_preloader_load’, 25 );
Check the parameters passed and probably leave them as they are if they are different from this
Also – if this doesn’t work can you post details about the error message you get?