<br />
<b>Fatal error</b>:  Cannot redeclare wp_admin_bar_header() (previously declared in /public_html/wp-includes/deprecated.php:5950) in <b>/public_html/wp-includes/admin-bar.php</b> on line <b>1208</b><br />
<br />
<b>Fatal error</b>:  Uncaught Error: Call to a member function set() on null in /public_html/wp-includes/l10n.php:854
Stack trace:
#0 /public_html/wp-includes/l10n.php(957): load_textdomain('default', '/public_html/wp...', 'pl_PL')
#1 /public_html/wp-includes/class-wp-fatal-error-handler.php(49): load_default_textdomain()
#2 [internal function]: WP_Fatal_Error_Handler-&gt;handle()
#3 {main}
  thrown in <b>/public_html/wp-includes/l10n.php</b> on line <b>854</b><br />