Page builder problem

Hi,
I’m using page builder with some others plugin on a website. After cheking potentials conflict between the differents plugins I use, I don’t find nothing. Sometimes if I disable a plugin, page builder works again, and sometimes I must disable an other one. Even if I disable all plugins, page builder still have problems and doesn’t work all the time.

I think there’s a problem with page builder itself or maybe with my theme cause something weird happen when I make change on my pages :
When it works, if a make a modification on a page, after saving it, the plugin crash. I have to disable page builder, actualize and then reactivate it to find my plugin working again. I’m not a developper so it’s difficult for me to find a solution (and i’m french hence the quality of my english)
Wish you could help me !
Thanks

Theme Flashlight Version : 2.4.1
Page builder Version 2.1.2
Wordpress Version 4.2.1