Update issue with l3kernel and siunitx

Hi All,

Today I updated my MikTex 2.9 install. After that I tried to compile my 
current project, but it resulted in an error when loading siunitx:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!
! LaTeX error: "kernel/command-not-defined"
!
! Control sequence \tl_replace_all_in:Nnn undefined.
!
! See the LaTeX3 documentation for further information.
!
! For immediate help type H <return>.
!...............................................

l.333 ...enerate_variant:Nn \tl_replace_all_in:Nnn
                                                    { NnV }
?

I tried reinstalling MikTex (as suggested by others online) but this 
didn't solve my problem. I tried manually installing the newest versions 
of CTAN of l3kernel and l3packages, but without success. A minimal 
working example also provides the same problem:

\documentclass{article}
\usepackage{siunitx}
\begin{document}
\section{test}
\end{document}

I have the following packing dates:
siunitx            2011-10-07
l3kernel         2011-09-16
l3packages    2011-09-19

Is this due to different update schemes? Does anyone else have this 
issue? Is there a way I can solve it?

Hope you can help.

Thijs

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