Error Message: "Current Configured Preferred Server is Not Available. Using 'PlugIn Server US (CBOE)'
Simply extract the plugin file (link provided below) to your %appdata%\OptionsOracle folder (Create one if you don't have it already there) and run options oracle. Hurrah the error is gone and you will now be prompted to update plugins as well. You should also be able to see the list of plugins available in the configuration option. Enjoy!!!
Problem: Problem is with the plugin file hosted by Samosky. It has a space missing in its plugin xml file which causes issues with the plugins (e.g. NSE)
File as updated on 02-Sept-2013