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 ...
I guess that Google removes already indexed pages that are now returning the HTTP error 403. Unfortunately I can't find any definitive statement on that matter. Do you know the answer?
I am wondering if a disallow directive needs to be issued to robots on pages that will generate: a 403 forbidden error; a blank page, or; a page redirect (to log in page for example). Would not ...