If I attempt to create a Vista firewall rule for an executable which is in my personal directory (under \Users\<username>\), the browse dialog substitutes environment variables like %APPDATA% or %USERPROFILE%. However, the firewall itself runs as a different user, so those variable substitutions are invalid. A full path must be used in these cases (eg. starting with C:\Users\<username>\).
BTW. The Blogger composer can't handle < and >. Instead I had to use < and >