After activation, if you received this error,
Change your permalink settings. uListing plugin requires Permalink Structure rather than “Plain”. We recommend to use “Post name” Permalink Structure.
Then go to Settings - > Permalinks and change Permalink setting to Post name.
After that, go to the demo import page where demo import page will appear.
Click “Run Demo Import”.
If you have problems during the demo import, look at the permalink settings once again.
Demo content imported, good job!