The Animate Package timeline option does not work [closed]

Question

I have written a very simple example to start applying the timeline option of the animate package in my presentations. The example is very much like the one in the manual "The Animate Package" by Alexander Grahn, in the 15th of April of 2016 version, page 16:

This is the example (in the tex file "Working_Example_Article.tex"):

\documentclass{article}
\usepackage{animate}
\usepackage{graphicx}

\begin{filecontents}{sample.tln} 
::0X0 %first frame repeated until the end 
::1
::2
::3
\end{filecontents}

\begin{document}

\begin{center}
\animategraphics[
label=sample,
scale=0.35,
loop,
timeline=sample.tln
]{4}{Sample_}{1}{4}
\end{center}

\end{document}

In the working directory, I have the files Sample_1.png, Sample_2.png, Sample_3.png, Sample_4.png (in fact, I have from 1 to 100). When I try to compile this code, by using the standard:

~$ pdflatex Working_Example_Article

I am unable to generate the corresponding pdf because compilation ends at:

(./Working_Example_Article.aux)
(/usr/share/texlive/texmf-dist/tex/latex/oberdiek/epstopdf-base.sty
(/usr/share/texlive/texmf-dist/tex/latex/oberdiek/grfext.sty)
(/usr/share/texlive/texmf-dist/tex/latex/oberdiek/kvoptions.sty)
(/usr/share/texlive/texmf-dist/tex/latex/latexconfig/epstopdf-sys.cfg))
<building timeline a0 from file `sample.tln':
! Argument of \_pbs_reftonum:w has an extra }.
<inserted text> 
                \par 
l.22     ...]{4}{Sample_}{1}{4}
                               ^^M

The thing is worrisome and weird because all I have done is building a simplified version of the first example of the manual I mentioned above. Any help? I will very much appreciate it!!!