Hi, I am trying to edit the default 'Access Denied' page inside the amember wordpress plugin, and can't seem to find the place to edit the error message: Access Denied! Sorry – This is a private area. Please login, or signup Thanks.
That is the default. You can build as many custom error messages as you want as described on this page of the Documentation Wiki. You then apply the custom error messages using the "Show this error message instead of page/post content" choice as described on this page of the Documentation Wiki. This is a much better approach than modifying core files.