Is the ver of office you are trying to install compatable with XP?
Is the disk clean? Sometimes a smudge of grease, from your (or your kids) fingers can affect the installation, as the affected area may not be able
to be read.
This is the MS knowledgeBase page click here for "Setup does not run or you receive an "Error opening installation log file" error message when you run Office 2000 Setup"
This page is the MS knowledgeBase entitled "How to use an Office 2000 Setup log file to troubleshoot Office Setup problems" click here It has pages for Microsoft Office XP and a link for Microsoft Office 2003.
This one click here
gives you a page of references to KB articles refering to Office.
Hope this helps.