mod security causes % sign to cause 'not acceptable error'

Question

Hey guys I was just curious if anyone had this problem before. When I go to my site url http://www.site.com/search.php?q=%25 or simply type a % sign in the search bar, I get

Not Acceptable An appropriate representation of the requested resource /search.php could not be found on this server. Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

I was told this was a product of mod security, so I was wondering if anyone had this problem before or knew a solution for it, or if not could recommend a good substitution for mod security since I know that sites like youtube do not have that problem when you perform the same procedure. Any advice greatly appreciated.