Reply from support
Here is the email reply I got from Blogger support:
Hi there,
We are only using port 21, so your settings should be fine. One thing to
check, though, is if you are using active FTP. We only support passive
FTP, so that could be causing the problem.
Sincerely, ******
OK, this makes sense. ANYBODY KNOW HOW TO CHECK THAT ON IIS6???? Sorry, I didn't mean to shout, but I'm too tired to look for myself.
email me if you know the answer.