为什么我不能在下面的代码中以通常的方式使用脚注？

Question

为什么我不能像通常一样在下面的代码中使用脚注，

\documentclass[oneside]{book}
\pagestyle{plain}


\usepackage{amsmath,amsthm,amssymb,xcolor,amscd,enumerate,verbatim,calc,graphicx,dsfont,geometry}
\geometry{a4paper}
\usepackage[hidelinks]{hyperref}
\usepackage{lmodern}
\usepackage{sectsty}
\usepackage{scrextend}
\usepackage{titlesec}
\usepackage[latin1]{inputenc}[2008/03/30]
\usepackage{ifthen}[2001/05/26]  
\usepackage{alltt}[1997/06/16]   %% boilerplate, credits, license
\usepackage[labelformat=empty]{caption}
\usepackage{array}[2008/09/09]   %% extended array/tabular features
\KOMAoption{fontsize}{11pt}

\sectionfont{\normalfont\bfseries}
\renewcommand{\sectionmark}[1]{}

\makeatletter
\newcommand\level[1]{%
  \ifcase#1\relax\expandafter\chapter\or
    \expandafter\section\or
    \expandafter\subsection\or
    \expandafter\subsubsection\else
    \def\next{\@level{#1}}\expandafter\next
  \fi}
 \newcommand{\@level}[1]{%
  \@startsection{level#1}
    {#1}
     {\z@}%
    {-3.25ex\@plus -1ex \@minus -.2ex}%
    {1.5ex \@plus .2ex}%
    {\normalfont\normalsize\bfseries}}

\newcounter{level4}[subsubsection]
\@namedef{thelevel4}{\thesubsubsection.\arabic{level4}}
\@namedef{level4mark}#1{}
\count@=4
\loop\ifnum\count@<100
\begingroup\edef\x{\endgroup
\noexpand\newcounter{level\number\numexpr\count@+1\relax}    [level\number\count@]
\noexpand\@namedef{thelevel\number\numexpr\count@+1\relax}{%
      \noexpand\@nameuse{thelevel\number\count@}.\noexpand\arabic{level\number\numexpr\count@+1\relax}}
\noexpand\@namedef{level\number\numexpr\count@+1\relax mark}####1{}}
  \x
  \advance\count@\@ne
\repeat

\makeatother
\setcounter{secnumdepth}{100}
\setcounter{tocdepth}{2}
\hypersetup{
colorlinks,
citecolor=blue,
filecolor=blue,
linkcolor=blue,
urlcolor=red
}
\hypersetup{linktocpage}
%    Some definitions useful in producing this sort of documentation:
\chardef\bslash=`\\ % p. 424, TeXbook
%    Normalized (nonbold, nonitalic) tt font, to avoid font
%    substitution warning messages if tt is used inside section
%    headings and other places where odd font combinations might
%    result.
\newcommand{\ntt}{\normalfont\ttfamily}
%    command name
\newcommand{\cn}[1]{{\protect\ntt\bslash#1}}
%    LaTeX package name
\newcommand{\pkg}[1]{{\protect\ntt#1}}
%    File name
\newcommand{\fn}[1]{{\protect\ntt#1}}
%    environment name
\newcommand{\env}[1]{{\protect\ntt#1}}
\hfuzz1pc % Don't bother to report overfull boxes if overage is < 1pc

%       Theorem environments

%% \theoremstyle{plain} %% This is the default
\newtheorem{thm}{Theorem}[chapter]
\newtheorem{cor}[thm]{Corollary}
\newtheorem{lem}[thm]{Lemma}
\newtheorem{prop}[thm]{Proposition}
\newtheorem{pro}[thm]{Property}
\newtheorem{prob}{Problem}[section]
\newtheorem{ax}{Axiom}
\newtheorem{case}{Case}[section]
\newtheorem*{conj}{Conjecture}
\newtheorem{claim}{Claim}
\newtheorem{subcase}{Subcase}[case]

\theoremstyle{definition}
\newtheorem{defn}{Definition}[chapter]

\theoremstyle{remark}
\newtheorem{rem}{Remark}[section]
\newtheorem*{notation}{Notation}

%\numberwithin{equation}{section}

 \newcommand{\thmref}[1]{Theorem~\ref{#1}}
 \newcommand{\secref}[1]{\S\ref{#1}}
 \newcommand{\lemref}[1]{Lemma~\ref{#1}}
 \newcommand{\eqnref}[1]{equation~\ref{#1}}
 \newcommand{\PGBoilerPlate}{%
    \pagenumbering{Alph}
  \pagestyle{empty}
  \BookMark{0}{PG Boilerplate.}
}
\newcommand{\FrontMatter}{%
  \cleardoublepage
  \frontmatter
  \pagestyle{empty}
}

%    \interval is used to provide better spacing after a [ that
%    is used as a closing delimiter.
\newcommand{\interval}[1]{\mathinner{#1}}

%    Notation for an expression evaluated at a particular condition. The
%    optional argument can be used to override automatic sizing of the
%    right vert bar, e.g. \eval[\biggr]{...}_{...}
\newcommand{\eval}[2][\right]{\relax
  \ifx#1\right\relax \left.\fi#2#1\rvert}

%    Enclose the argument in vert-bar delimiters:
\newcommand{\envert}[1]{\left\lvert#1\right\rvert}
\let\abs=\envert

%    Enclose the argument in double-vert-bar delimiters:
\newcommand{\enVert}[1]{\left\lVert#1\right\rVert}
\let\norm=\enVert

\begin{document}
\frontmatter
\pagestyle{empty}
\begin{titlepage}
\begin{center}
\vspace*{5cm}
\begin{huge}\textbf{First Line of the Title}\end{huge}\\[2mm]
\textit{Second Line of the Title}\\[5cm]
\begin{large}\textsc{Auhor}\end{large}
\end{center}
\end{titlepage}
\tableofcontents
\mainmatter
\chapter{First Chapter%
\footnote{Some text.}}
\section{First Section%
\footnote{Some text.}}
\subsection{First Subsection%
\footnote{Some text.}}
\end{document}