an error message about a library I don't even have

I have compiled a asp.net project that does use security features like membership and roles.  But when I run it on my local PC, I get an error about libraries that I don't even have.  For instance:
<add name="MySQLRoleProvider" type="MySql.Web.Security.MySQLRoleProvider, MySql.Web, Version=6.7.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" connectionStringName="LocalMySqlServer" applicationName="/" /> I did a search through my entire project, including the web.config to find this line.  Its NOWHERE in my project.
I have installed the MySql library on my PC for a totally different website.  But this website just doesn't have it anywhere.  And yet I get error messages about it.  Whats going on?
-- Here is the entire error page.  at one point it mentions a "machine.config":
Configuration Error Description: An ...