TL;DR: If the problem occurs to you, please downgrade to version 4.0.0. I’ll update this plugin as soon as a fixed version is released by the Hyphenator.js developer. You might also think about your site’s domain configuration.
Sorry for not responding to this thread. I’m not actively maintaining this plugin since I stopped using WordPress and also couldn’t really test it. As you likely noticed this plugin just uses the JavaScript “Hyphenator.js” which does the hyphenation work. It seems like a problem there that is not related to my code.
This really seems related to some same origin policy which will be an issue if the url in the browser address bar differs from the url that is set in the WordPress configuration and used for embedding the JavaScript resource file. Can you confirm this only happens in this special case?
Besides from the nasty error message, this setup isn’t recommended. WordPress sites should only be available using a specific domain. If you would like to use multiple domains for your site, please think about having a default domain and redirecting the others to that one. This is also bad in case of SEO, since Google might vote your site down because of the misuse of multiple domains and making the same content available on multiple sites using different domain names.
Even I stopped maintaining this plugin, I would like to update it when a fixed version of Hyphenator.js is released. So this plugin should work at least as long as future WordPress versions won’t break any used APIs.
@benjamin Pick: Nice hack. I plan to add an option for directly writing the configuration code in the next version.
@sfbarth: The file with the debug suffix is the raw source code used for development, the normal file used by the plugin is a highly size optimized version using short variable names, less whitespaces etc. It does exactly the same and provides the same results even it has a different look.