[XeTeX] Problem with xelatex/fontspec/xparse.sty with miktex2.9

[sjo]

Hi, I have just installed miktex2.9. The use of \usepackage{fontspec}
produces and Undefined control sequence error in xparse.sty:

------------
% !TEX TS-program = xelatex
% !TEX encoding = UTF-8
\documentclass[11pt]{article}
\usepackage{fontspec}
\begin{document}
Problem with xparse.sty
\end{document}
--------------
Error:
("C:\Program Files (x86)\MiKTeX 2.9\tex\latex\l3packages\xparse\xparse.sty"
! Undefined control sequence.
<argument> \filename
l.57 ...\filedate}{\fileversion}{\filedescription}
?
-----------------------------------

I had to install l3packages and other l3* stuff to get xelatex to work
with the above file.

Any help would be much appreciated.

Jon