Smush Pro 2.1.3 does not work with Visual composer 4.9.2

I can't smush not even one image unless I disable Visual Composer 4.9.2 (latest version). The button spins. I inspected the element - Console:

"Uncaught TypeError: Cannot read property 'error_msg' of undefined" for wp-smushit-admin.js line 266"

As soon as I disable the Visual composer 4.9.2, I can smush files.

Obviously I don't have to mention that Visual composer is key to almost any website (permit the usage of dozens of shortcodes and visual rich edition).

Please tell me you have a fix for this. I've just bought the plugin and this is a big let down.

Cheers
Ramiro.