hi, please look at this: mck.art.pl/

since yesterday I have a big problem with my website.
I don't change anything inside CMS but now I have a lot of error-messages, like:

Notice: Undefined index: 1 in /home/potls/domains/mck.art.pl/public_html/templates/jf_texturia/scripts/php/mainmenu.php on line 47
Notice: Use of undefined constant add_css - assumed 'add_css' in /home/potls/domains/mck.art.pl/public_html/plugins/content/sexybookmarks/sexybookmarks.php on line 49
Notice: Undefined variable: sendMessage in /home/potls/domains/mck.art.pl/public_html/modules/mod_simplecontact/mod_simplecontact.php on line 52

Could it depend on changes in the hosting account or someone had broken website protection? As I said I don't change anything.
what should I do to fix it? :/

Hi, please ask your hosting provider if php version has been updated.
You can also try to switch off php errors in .htaccess

# disable php errors
php_value docref_root 0
php_value docref_ext 0
php_flag html_errors off
php_flag display_errors off
php_flag display_startup_errors off

# php error logging
php_flag log_errors on
php_value error_log /path/domain/your-desired-folder/PHP_errors.log

# protect php error log
<Files PHP_errors.log>
Order allow,deny
Deny from all
Satisfy All
</Files>