I am using the WP No External links plugin since a year now and never had any issues. When I checked Google Webmaster tools for my site I noticed a lot of 403 Access Denied errors started to come up from the end of October for links that are masked with the plugin. None of my masked links seem to work.
I also use a plugin called BBQ Block Bad Queries to secure my WordPress. The plugin seems to block the redirect and when deactivated the redirect via /goto/URL works fine.
Is there anything I can do to make this work without deactivating one of the plugins?