The Meiryo UI font is available for Windows Vista and for Windows Server 2008
This article describes an update to the Meiryo Japanese font family for Windows Vista and Windows Server 2008. This font family now includes the Meiryo UI font and the Meiryo UI Bold font. This new font lets applications display Japanese text more clearly in the new Ribbon UI component. The Ribbon UI component can be used in many applications that run on Windows Vista or on Windows Server 2008.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB975929.