Hi, I just ran into a similar issue and discovered there is a word press conflict with some zip files believe it or not. I uploaded this plugin that fixed my issue. All you do is upload the plugin and you can load your them with no issues. the plugin can be found at this link: https://github.com/aaronjorbin/force-pclzip/releases/tag/0.1
There are two options to choose from. I chose “source code zip”
Good luck,
Serge
