Problem with page editing and saving

[Tazavoo]

Fatal error: Call to undefined function json_encode() in /var/www/html/test/gs_debug/admin/inc/template_functions.php on line 761

json_encode should be available from PHP 5.2.0 onwards, but maybe it is disabled on your website?

BTW: disabling plugins doesn't always work as expected - to make sure there are no side effects from a plugin, delete it or rename the plugin file to something else, e.g. i18n_navigation.php.bak

I've sent my host a mail now asking them about json_encode, hopefully they can do something about it! Thank you for the tip about plugins!