Oops sorry about that. Yes. You are correct. The wp-admin Custom Code solution is here: http://forum.ait-pro.com/forums/topic/search-string-403-error/#post-14372
Well personally, technically and using best security practices I would not allow a single quote code character (or the URL encoded %27, which is the same thing) in a Query String if I was the creator of that plugin. By default WordPress strips out single quote code characters from any/all Post or Page URL’s|URI’s when you save any/all Posts or Pages. And that is exactly what I would do as well if I was the creator of that plugin, but most likely people would complain about that. So my guess is that apostrophe’s|single quote code characters are not being stripped out in that plugin for that reason. 
- This reply was modified 3 hours, 34 minutes ago by AITpro Admin.