I think that problem is not that those urls cannot be fetched by wl. I think that wl cannot get the blog page at all since wl does not support form authentication. check error log and see what wl says. error log can be found at:
To check the error log of Windows Live Writer, go to the “Help” then “About Windows Live Writer” menu on Windows Live Writer itself. Look at the “Show Log File” link on that window, click over there to locate the error log and then open that to see the list of errors. Most recent error will appear at the bottom of that log file.
Checked the log file, and no errors are logged. Here is the log information:
Found a work around, see: