Recently I changed some of my sites to not use the "www" on the front of the URL. It was a little tricky but I got it working right. The first part is to change WordPress to use shorter URL. The second part of the change was to modify the .htaccess file. I found that the post, Comprehensive URL Canonicalization via htaccess for WordPress-Powered Sites, helped me the most. I checked it in a browser and everything looked fine. Much later I tried to write a post in LiveWriter and it did not work. It gave me the following error message.
blogger.getUsersBlogs method received from the weblog server was invalid
After a little debugging I figured out I could get rid of the problem if I refreshed my account settings for the web sites with the new .htaccess file. I guess LiveWriter is picky about the web site URL.