Hi, 

this is just perfect... I've discovered that instead of child theme, the actual The Gem was active, so I clicked on Activate button on the Child theme and the got the WP critical error message right away.
The only significant thing to WP I did is to shut up the plugin update notifications in the functions.php, because the Layer Slider wouldn't update and got error message about a missing package or something...

So now I can't work on my site any more.

Regards

Okay, just deleted this entry from functions.php and everything is working again:

// hide update notifications
function remove_core_updates(){
global $wp_version;return(object) array('last_checked'=> time(),'version_checked'=> $wp_version,);
}

add_filter('pre_site_transient_update_plugins','remove_core_updates'); //hide updates for all plugins