I've installed a hfslipped XP with all the MSXML files from the Current Windows XP SP2 updates (including MSXML 6.0), and then installed Visual Studio 2005. After that I wanted to install SQL Server Management Studio Express Edition (SSMSEE) but it asked me for MSXML 6.0 which as said before was already on the system. I could finally install SSMSEE by installing MSXML 6.0 again (same file I hfslipped). What could be the source of this problem? Thanks in advance.

Not sure if this is the same problem but I think I read on a KB article page for Visual Studio that if you install MSXML6 SP1 and then Visual Studio, the MSXML6 SP1 files will be overwritten by the "SP0" versions that come with Visual Studio. You may have to slipstream updates into SQL Server Management Studio Express Edition that work around this issue if possible.

Owww, bad luck I guess; thanks for the answer.