I host with WPEngine and made sure to reset file permissions on each setup but it says "Remote server returned error response" so I'm wondering if it's file permissions on the host of the sample data.
Well you can ignore these warnings .i guess the import was successfully done at your end and most of the media has been imported .
If you find the media to missing form any demo page then just report it us .
Looks like it's not the the images. Some of the quizzes have wrong import data (see The Software Quiz attached).
I have used wordpress reset and tried the install multiple times on WPengine
This happens in some of the cases die to mismatch of the post ids .Sometimes we also face these kinda errors .
You can remove these question from the imported quiz .
We are trying to improve the import function in wplms .