403 Forbidden page

Hi there,

I'm trying to add a new page using Wordpress page tool, adding a couple of words, phrases and saved it.

But when I clicked "Preview", I get window pop saying "Forbidden: You do not have the permission to access this document."

I checked the permissions settings using CoreFTP and grant read/write/execute priviledges on the folder I want this page to publish, but still won't do. I tested a dummy html under the same folder and it came out okay. But not the page I created at Wordpress admin page. So I'm not sure what user account should I use to grant the correct privileges?