robcnz on "Customizr header & footer stopped working"

Crikey - now my entire site has crashed and I can't seem to get it up and running again.

The error I am getting is:
"exhausted (tried to allocate 71 bytes) in /home/learni67/public_html/wordpress/wp-includes/meta.php on line 578"

I've tried taking out the child theme header.php and the meta.php files but that doesn't work.

I've looked at the meta.php file and it has the following code in it:

// Force subkeys to be array type:
			if ( !isset($cache[$mpid]) || !is_array($cache[$mpid]) )
				$cache[$mpid] = array();
			if ( !isset($cache[$mpid][$mkey]) || !is_array($cache[$mpid][$mkey]) )
				$cache[$mpid][$mkey] = array();

But I have literally no idea where to start, the line which the error refers to is the last one:

$cache[$mpid][$mkey] = array();

help!