Hey dpbardell,

The 'Update package not available' or similar error messages during the update process, are most likely symptoms of an interfering 3rd party theme or plugin.   
We are constantly notifying and working together with various authors whenever we notice such issue. 
Unfortunately, these issues cannot be fixed from our end and a temporary solution is updating manually or temporarily disabling other plugins and switching to the default WP theme.  

In case of a manual update, you will need to completely remove the current version first, as there cannot be two instances of the plugin present on your installation. 
Please note that your sliders and settings are stored in the database so they won't be deleted in the process.
You can also find detaled installation instructions in the documentation, please refer to the following URL: https://support.kreaturamedia.com/docs/layersliderwp/documentation.html#plugin-setup

Another possibility might be a stuck activation. If you've used our online tools to remotely deactivate a site (or asked us to do the same on your behalf) your site might no longer be activated. The same can be true if your purchase code has been revoked due to a refund or another reason.   
In cases like this deactivating your site and then immediately re-activating it can help.