! Undefined control sequence.

Questo codice
`\documentclass{ltxdockit}

\usepackage{xltxtra}
\setmainfont[Numbers=OldStyle]{TeX Gyre Bonum}
\setsansfont[Ligatures=TeX,Scale=MatchLowercase]{Candara}
\setmonofont[Ligatures=TeX,Scale=MatchLowercase]{Consolas}
\usepackage{polyglossia}
\setdefaultlanguage{english}
\PolyglossiaSetup{english}{indentfirst=false}

\renewcommand\contentsname{table of contents}
\addtokomafont{sectionentry}{\rmfamily\mdseries\scshape\lowercase}
\addtokomafont{section}{\rmfamily\mdseries\scshape\color{spot}\lowercase}
\addtokomafont{subsection}{\rmfamily\mdseries\itshape\color{spot}}
\makeatletter
\def\@seccntformat#1{\protect\makebox[0pt][r]{\csname
the#1\endcsname\hspace{\marglistsep}}}
\makeatother

\definecolor{spot}{rgb}{0.6,0,0}
\definecolor{boxframe}{rgb}{0.6,0,0}
\definecolor{boxfill}{rgb}{1,.95,.95}

\usepackage{verbatim}
\usepackage{upquote}
\newcommand{\midtilde}{\raisebox{-0.30\baselineskip}{\textasciitilde}}

\lstnewenvironment{example}[1][]
{\lstset{%
aboveskip=1.5\lstenvsep,
xleftmargin=3pt,
xrightmargin=3pt,
frame=single,
backgroundcolor=\color{boxfill},
rulecolor=\color{boxframe},
framesep=2.5pt,
framerule=0.5pt,
style=latex,#1}}
{}

\hypersetup{linkcolor=black,urlcolor=black}

\title{\textsf\huge{\spotcolor xindy}}
\author{\mdseries\itshape\Large\spotcolor A fle\textbf{x}ible
\textbf{ind}exing s\textbf{y}stem}
\date{}

\begin{document}
\maketitle

\textbf{xindy} to a completely different system can mostly be done by writing
an appropriate raw index filter.

The format of the raw index interface of \textbf{xindy} is defined as follows:

\begin{verbatim}
(indexentry { :key string-list [:print string-list]
| :tkey list-of-layers }
[:attr string]
{ :locref string [:open-range | :close-range]
| :xref string-list } )
\end{verbatim}

\end{document}`
alcuni giorni fa compilava. Stasera non ne vuol sapere:
`! Undefined control sequence.
\initiate@active@char

l.48 \begin{document}

? `
Eppure non mi pare di aver apportato modifiche,
e non capisco a che cosa si riferisca l’errore…

m