Forbidden Error ( 403 )

Hi:
I’m experiencing a strange error on my new installation of WordPress (3.0.1) Everything works except the submission of comments. Doesn’t matter whether logged in or not.

Page says: Forbidden.”You don’t have permission to access https://xxxxxxx.xxxxxxx.net/wp-comments-post.php on this server.”

It only happens when I or any one of my friends submits a comment. I know there are numerous postings regarding comments and blank pages and other things.
This seems to be something else.
Just in case, I have no plugins active and my folder security settings from the root folder down allow modification and writing.

I’ve never had this before and I’m quite perplexed.
Any assistance would be greatly appreciated.

Thank You