Sorry to be the bearer of bad news but there is a potential conflict with other plugins. One of them is GP Premium where it doesn’t let me import settings, see screenshot. After deactivating both WPsp and WPsp pro or WPsp pro only i can then import GP Premium settings.
Another possible conflict:
I use the Toolset plugin wp-types for CPT and when I have the wp-show-posts pro plugin active I get the following error when I go into Toolset >> Post Types
I deactivate Pro and no error…