0. Please make sure that your TeX distribution is up-to-date.
LuaTeX-ja (luatexja-fontspec.sty) requires xunicode.sty v0.981.
-1. If you use TeX Live 2011 or later, you can install LuaTeX-ja via tlmgr.
+1. If you are using TeX Live 2011 or later, you can install LuaTeX-ja via tlmgr.
2. If you must/want to install manually:
a. Download the source archive from CTAN,
or tagged as $VER$ in the Git repository by
<http://git.sourceforge.jp/view?p=luatex-ja/luatexja.git
- ;a=snapshot;h=$VER$;sf=tgz>
+ ;a=snapshot;h=refs/tags/$VER$;sf=tgz>
b. Extract the archive and put src/ into your TEXMF tree.
An example location is TEXMF/tex/luatex/luatexja.