# ! Undefined control sequence. l.52 \char_make_active:n {"20}% [closed]

This is the XeTeX code I copied from Wikipedia, theoretically it must be working:

\documentclass[11pt]{article}
\usepackage{xltxtra}
\setmainfont[Mapping=tex-text]{Linux Libertine O}
\begin{document}
\section{Unicode support}

\subsection{English}
All human beings are born free and equal in dignity and rights.

\subsection{Íslenska}
Hver maður er borinn frjáls og jafn öðrum að virðingu og réttindum.

\subsection{Русский}
Все люди рождаются свободными и равными в своем достоинстве и
правах.

\subsection{Tiếng Việt}
Tất cả mọi người sinh ra đều được tự do và bình đẳng về nhân phẩm và
quyền lợi.

\subsection{Ελληνικά}
Ὅλοι οἱ ἄνθρωποι γεννιοῦνται ἐλεύθεροι καὶ ἴσοι στὴν ἀξιοπρέπεια
καὶ τὰ δικαιώματα.

\section{Legacy syntax}
When he goes---Hello World!''\\
She replies—“Hello dear!”

\section{Ligatures}
\fontspec[Ligatures={Common, Historical}]{Linux Libertine O Italic}
\fontsize{12pt}{18pt}\selectfont Questo è strano assai!

\section{Numerals}
\fontspec[Numbers={OldStyle}]{Linux Libertine O}Old style: 1234567\\
\fontspec[Numbers={Lining}]{Linux Libertine O}Lining: 1234567

\end{document}


I used TeXworks and XeLaTeX to compile, it asked me to download a bunch of packages but in the end it only gave me this error:

! Undefined control sequence.
l.52 \char_make_active:n
{"20}%


This LaTeX really makes me crazy, for the lack of Unicode support and every solution to get around this problem seems to be equally painful. But I have to use LaTeX for my thesis, so, so you know how to fix the damn error above or any other way to add multi-language Unicode support feature to LaTeX?

Thanks.

By the way, my thesis is about human languages, so the support for CJK (Chinese, Japanese, Korean, Thai, Vietnamese) and some Western languages are needed.

-

## closed as too localized by Joseph Wright♦May 6 '12 at 8:12

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Welcome to TeX.SX. I don't get any error. What TeX distribution are you using and on what operating system? –  egreg Apr 5 '12 at 23:14
This is most likely due to having the wrong combination of versions for various packages (in particular, \char_make_active:n is from the expl3 package). Try updating your installation if possible. If that does not fix the issue, please add \listfiles at the top of your document and provide us with the file list hence produced in the .log file. –  Bruno Le Floch Apr 5 '12 at 23:18
Here is the log file I'm using MikTeX 2.9 (newest version I believe) on Windows 7. –  Unnamed Apr 5 '12 at 23:59
Your log-file ends in the middle which means that you killed the xetex window. Don't do this. Type x + then hit enter at the console prompt so that xetex can close the log-file correctly. Then we can see line 52 of which file gives the problem. I can compile your document without problems and as far as I can see from your incomplete log file your package versions are up-to-date. But documents can be changed during copy&paste so it would be better if you put it and the (complete) log-file in a zip-file. –  Ulrike Fischer Apr 6 '12 at 10:08
Actually, typing q instead of x may give even more information. I otherwise agree with Ulrike. –  Bruno Le Floch Apr 6 '12 at 10:09