LaTeX compiling error if more sections are added: "Undefined control sequence"

After several hours of trying to find the error that was making the compilation fail:

Undefined control sequence. \listoffigures

Resulted that this error has nothing to relate to figures, neither tables.

It seems that I have reached a section max number limit (yes, it seems incredible also for me): if add another \section{title} to any of the .tex files that are called in the project, the error of Undefined control sequence. will arise.

And, curiously, this max number of sections seems to be the number of sections that fit in a single page of the Table of Contents:

So, I have no idea how to deal with this.

I am stuck and I simply cannot add any more sections \section{title} to my .tex project.

Code in the main document (which calls other .tex files that are very simple and contain only commands for sectioning, tables, figures, and tikz pictures with captions):

\documentclass[11pt, twoside, draft]{report}

\usepackage[utf8]{inputenc}
\usepackage{graphicx}
\usepackage[a4paper,width=150mm,top=25mm,bottom=25mm,bindingoffset=6mm]{geometry}
\usepackage{fancyhdr}
\usepackage{subcaption}
\usepackage[numbers,sort&compress]{natbib}
\usepackage{color,soul}
\usepackage{xcolor}
\usepackage{pgfplots}
\usepackage{tikz}
\usepackage{booktabs}
\usepackage{tabularx}
\usepackage{longtable}
\usepackage{tabu}
\usepackage{array}
\usepackage{colortbl}
\usepackage{hyperref}
\usepackage{xr}
\usepackage{textcomp}
\usepackage{courier}
\usepackage{graphicx}
\usepackage{caption}

\captionsetup{font=footnotesize, labelfont=sc}
\graphicspath{ {images/} }
\pagestyle{fancy}

\definecolor{bblue}{HTML}{A9D0F5}
\definecolor{lightbblue}{HTML}{CEF6EC}
\definecolor{darkbblue}{HTML}{4189F5}
\definecolor{ggreen}{HTML}{D8F6CE}
\definecolor{darkggreen}{HTML}{41F583}
\definecolor{verydarkggreen}{HTML}{31B404}
\definecolor{rred}{HTML}{F5A9A9}
\definecolor{verydarkrred}{HTML}{DF0101}
\definecolor{oorange}{HTML}{F5ECCE}
\definecolor{verydarkoorange}{HTML}{DF7401}
% \def\tabularxcolumn#1{m{#1}} This is for vertical centering in tabularx.

\pgfplotsset{every tick label/.append style={font={{\scriptsize}}}}
\pgfplotsset{/pgf/number format/use comma}
\pgfplotsset{compat=1.5}

\input{Chapters/01_Title}

\input{Chapters/02_Abstract}

\pagestyle{fancy}
\let\Chaptermark\chaptermark
\def\chaptermark#1{\def\Chaptername{#1}\Chaptermark{#1}}
\fancyhead{}
\fancyhead[L]{\small \emph{Title}}
\fancyhead[R]{\small Author name}
\fancyfoot{}
\fancyfoot[R]{\small \thepage}
\fancyfoot[L]{\small \emph{Chapter \thechapter. \Chaptername.}}

\tableofcontents

\listoffigures

\listoftables


\chapter{Presentation}
\externaldocument{Chapters/03_Presentation}
\input{Chapters/03_Presentation}

\chapter{Introduction}
\externaldocument{Chapters/04_Introduction}
\input{Chapters/04_Introduction}

\bibliographystyle{IEEEtran}
\bibliography{References/Bibliography_report}

\appendix

\chapter{Appendix}
\externaldocument{Chapters/99_Appendix}
\input{Chapters/99_Appendix}

\end{document}

Thank you in advance for your help.

EDIT Nº1 This is the error log near to the ! indicator. [...]

] (./Report.toc
LaTeX Font Info:    External font `cmex10' loaded for size
(Font)              <10.95> on input line 2.
LaTeX Font Info:    External font `cmex10' loaded for size
(Font)              <8> on input line 2.
LaTeX Font Info:    External font `cmex10' loaded for size
(Font)              <6> on input line 2.
 [4

])
\tf@toc=\write4
\openout4 = `Report.toc'.


! Undefined control sequence.
<argument> Chapter \thechapter . \Chaptername 
                                              .
l.95 \listoffigures

The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

[5] (./Report.lof)
\tf@lof=\write5
\openout5 = `Report.lof'.

 [6

] (./Report.lot
Overfull \hbox (1.74966pt too wide) in paragraph at lines 4--4
 [][] []\OT1/cmr/m/n/10.95 Summary of power-trains used and/or de-vel-op-ment i
n pas-sen-ger light-weight |
 []

)
\tf@lot=\write6
\openout6 = `Report.lot'.

 [7

]
Chapter 1.

[...]

By the way, this error has something to relate with the auxiliary files result of the compilation, because if get the error, and then I delete the sections that "exceed", I keep obtaining the same error. I need to erase all the auxiliary files, and then if I compile (respecting this apparent max number of sections in the .tex project), it works; but obviously I will need soon or later to add more sections.