I'm facing the same problem with Googlebot not able to crawl my page. Mine problem doesn't have anything to do with
www or not. Google can crawl all my pages except one directory and this directory contains all images, no code. (I have other images directory and Googlebot can crawl fine).
When checking Google Webmaster Tools for Crawl Error, the directory which Googlebot couldn't crawl and yield "Access Denied" error is: http://www.artistviewpoint.com/picture-to-painting/pictures/samples/.
Reading the guide from Google, I have already checked my robots.txt file and there is no log-in authentication of any sort. The only remaining tips which Google provide is to check the hosting provider or authentication using proxy which I do not know how to check.