My finger would be pointing at the XML configuration files that Windows Live Writer uses; when they get corrupted, weird things happen.
I think referencing one of the developers is going to be your ticket.
You can email your LOG file to wlw-team@microsoft.com?
You can find your LOG file by opening up Writer, going to Help > About Windows Live Writer and then clicking the "Show log file" link in the About dialog.
Hope this helps.
Thanks,
L. Henry Jr.
http://www.lehsys.com