Previously working code no longer working and giving errors

I am writing a thesis using my institution’s thesis template. Previously, my working code works just fine. I don’t work on that for a few months. When I try to run it again yesterday, I get lots of errors. I use TeXstudio and MikTeX. My working code is as follows:

makeatletter
letmy@xfloat@xfloat
makeatother

documentclass[oneside,12pt,a4paper]{book}
%documentclass[12pt,a4paper]{book}
usepackage{UTMThesis, enumerate, amsfonts, longtable, qtree, etoolbox, array, rotating, pgf, tikz, tikz-cd, algorithm, csquotes}

makeatletter
def@xfloat#1[#2]{
    my@xfloat#1[#2]%
    defbaselinestretch{1}%
    @normalsize normalsize
}
makeatother

allowdisplaybreaks
usetikzlibrary{arrows, matrix, positioning, shapes, shapes.geometric, calc, intersections, decorations.pathreplacing}
newcommand{tikznode}[2]{relax
    ifmmode%
    tikz[remember picture,baseline=(#1.base),inner sep=0pt] node (#1) {$#2$};
    else
    tikz[remember picture,baseline=(#1.base),inner sep=0pt] node (#1) {#2};%
    fi}
letopenboxrelax
letiintrelax
letiiintrelax
letiiiintrelax
letidotsintrelax

newcommand*{qed}{hfillensuremath{square}}


%-------------------------------------------------------------
usepackage{cite}[sort] % change  cite from [1,2,3] to [1-3] etc for number system
makeatletter                        % change from
  renewcommand{@biblabel}[1]{#1.}  % [1] to 1. etc 
makeatother                         % in list of references
%-----------------------------------------------------------
  setlength{voffset}{-2.1cm}
  setlength{hoffset}{-.4cm}  
%--------------------------------------------------------
fontfiverm=cmr5 input{Pictex.tex} % using pictex
%---------------------------------------------------------
%pagestyle{plain}
%-------------------------------------------------------
  usepackage{fancyhdr}
  pagestyle{fancy}
  lhead{}
  chead{}
  rhead{}
  lfoot{}  
  cfoot{vspace{-.35cm}thepage}  % 
  rfoot{} 
  renewcommand{headrulewidth}{0pt}
%-------------------------------------------------------
begin{document}
frontmatter
  input{frontmatter/FrontTitle}
  input{frontmatter/Validation.tex}
  input{frontmatter/SupervisorDeclaration.tex}
  input{frontmatter/Title.tex}
  input{frontmatter/Declaration.tex}
  input{frontmatter/Dedication.tex}
  input{frontmatter/Acknowledgement.tex}
  input{frontmatter/Abstract.tex}
  input{frontmatter/Abstrak.tex}
%  tableofcontents
  input{frontmatter/TableofContents(Final).tex}  
  %input{TableofContents(Final1).tex}
  input{frontmatter/ListofTables(Final).tex} 
  input{frontmatter/ListofFigures(Final).tex}  
  input{frontmatter/ListofAbbreviations.tex}
  input{frontmatter/ListofSymbols.tex}
mainmatter
  input{main/Chap1.tex}        %Chapter1
  input{main/Chap2.tex}        %Chapter2
  input{DummyChapter.tex}
  input{main/Chap3.tex}        %Chapter3
  input{DummyChapter.tex}
  input{main/Chap4.tex}        %Chapter4
  input{DummyChapter.tex}
  input{main/Chap5.tex}    
  input{main/Chap6.tex}    %Chapter5
  input{main/Chap7.tex}
  input{ThesisRefUTMn(Final).tex}%
  input{DummyChapter.tex}
   input{main/ListofPublications}
  input{DummyChapter.tex}
   input{main/AppendixA.tex}
  input{DummyChapter.tex}
   input{main/AppendixB.tex}
backmatter
end{document}

and the errors that I get is as follows:

My complete working code can be obtained through this link:

https://drive.google.com/file/d/1Rk-SSZDNpN5BIhQtThF08SU0D0z-jnR-/view?usp=sharing

Please, how to solve this?