If you read the_guy's post above, as well as the directions on Tomcat's page, KB900325 is for XP Media Center Edition. You do not need it for your OS! If you want to include the Windows Media Player 9/10 codecs, you need to extract wmfdist95.exe out of the KB900325 hotfix.Now, please don't come back here until you sort out your hotfixes (as above). HFSLIP is not for people who don't read simple directions. I am trying to slipstreaming my source to xp sp2, then, I should check the "Service Pack 2" box rather than "Service Pack 1a", right? I have removed KB900325 from my HF folder, I still got the same error. Removed the media center and I replaced the msxml2sp6 to msxml4sp2-kb887606-x86-cht.exe. Still got the same error. When I click the MSXML 4.0 SP2 Other languages (msxml.msi) + latest binary update in the same language box, it shows me msxml.msi and msxml4sp2-kb887606-x86-enu.exe I am runing HFSLIP in a Traditional Chinese windows 2000 machine with an account with Admin privileges. The HFSLIP didn't warn me about my source is not clean and cannot slipstream Windows Update Agent. Here is the string you are looking for - Localization=Traditional Chinese By the way, the source is already slipstream to sp2 before I ran hfslip. However, I put the WindowsXP-KB916281-x86-CHT.exe in my HF folder because I've got a error just after entering the gui installation screen(something says root structure damaged). So I want to use hfslip slimstream the sp2 again to see if it fix the error.