I'm getting problems posting on my small WordPress site. After I give a publish in the admin screen then your page where this publish is displayed goes blank. Other pages will work fine -- just the page where that specific publish is displayed goes blank.
You've got a php_error due to the faq builder wordpress plugin. I recommend that you simply disable this wordpress plugin and install another FAQ wordpress plugin. I would recommend that you employ FAQ You wordpress plugin, used this on many sites without problems previously.
Should you still desire to use FAQ Builder, by searching in the error you'd sent, you are able to still repair it to really make it work by altering the plugin's code.