Hi All,
I am sure you all know about this already, but I thought I will mention it here for people in my situation. I had the same problem and I searched the internet for the solutions and even changed my php.ini settings, did .gz import to no avail and then I stumbled upon the following link and guess what? I was importing the .XML without actually activating the theme for which the post types and data was related to, as soon as I activated the theme all the errors went away.
https://themeforest.net/forums/thread/wordpress-demo-content-import-invalid-post-type-issues/83990?page=1
Apparently WP can’t import posts of a non-existing type.
Hope it helps someone ??
