As it says on the page.. "This skin [only] works with Messenger versions 8.5 (
why?)"
If you'd like a Vista-style skin for WLM 2009, see:
Vista United Skin.
From a design perspective, WLM 8.5 to 2009 was a massive change, so updating skins such as "Life of Vista" to work with 2009 unfortunately isn't a simple job and only the creator of the skin would know how to do so, so you'd have to ask them.
At the moment we're looking forward to WLM 2010 and seeing where skinning goes from there. See
Menthix's reply to "Is skinning dead?" for more info.
/ 
