xp pro multilingual can only be upgraded on top of xp pro (english) it cannot be upgraded on top of home... u need to f-disk your drive to remove the partition then try it.
What is Multlingual User Interfaced Pack (MUI)?
Multilingual User Interface Pack is a set of language specific resource files that can be added to the English version of Windows Professional. When installed on the English version of Windows, MUI allows the user interface language of the operating system to be changed according to the preferences of individual users to one of the 33 supported languages. This allows large corporations to roll out the same worldwide image with a single install job. Local users can then select the user interface language or it can be set by Group Policy for Organizational Units.
MUI also allows different language users to share the same workstation or roaming users to take their localized user interface from one workstation to another. For instance, one user might choose to see system menus, dialogs and other text in Japanese, while another user logging onto the same system might prefer to see the corresponding text in French.