[Tex/LaTex] \multicolumn not working

Question

What am I doing wrong? Can't figure it out! Keep receiving \multispan \omit.

Thanks

\begin{center}
    \begin{tabular}{|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|}
        \hline
        \textbf{taxa de amostragem} & \multicolumn{4}{|c|}{\textbf{44.1k Htz}} & \multicolumn{4}{|c|}{\textbf{48k Htz}} & \multicolumn{4}{|c|}{\textbf{96k Htz}} & \multicolumn{4}{|c|}{\textbf{192k Htz}}\\
        \hline
        \small  \textbf{duração da amostra (ms)} & \small \multicolumn{4}{|c|}{0.0226} & \small \multicolumn{4}{|c|}{0.0208} & \multicolumn{4}{|c|}{0.0104} & \multicolumn{4}{|c|}{0.0052} \\
        \hline
        \small  \textbf{tamanho do bloco} & \small 128 & \small 256 & \small 512 & \small 1024 & \small 128 & \small 256 & \small 512 & \small 1024 & \small 128 & \small 256 & \small 512 & \small 1024 & \small 128 & \small 256 & \small 512 & \small 1024 \\
        \hline
        \small \textbf{duração do bloco (ms)} & \small 2.90 & \small 5.80 & \small 11.60 & \small 23.21 & \small 2.66 & \small 5.33 & \small 10.66 & \small 21.33 & \small 1.33 & \small 2.66 & \small 5.33 & \small 10.66 & \small 0.66 & \small 1.33 & \small 2.66 & \small 5.33 \\
        \hline
    \end{tabular}
\end{center}

Answer 1

I'd rather propose this layout, if it has to fit an ordinary size of paper, with rows and columns swapped, a,d loadin siunitx for the alignment of numbers, and a proper typing if numbers with units:

\documentclass{article}
\usepackage{array, makecell, multirow}
\renewcommand{\theadfont}{\small\bfseries}
\usepackage{siunitx}

\begin{document}

 \begin{center}
\setlength{\extrarowheight}{2pt}
\sisetup{detect-weight, table-number-alignment=center}
 \begin{tabular}{|c|c|S[table-format=4.0]| S[table-format=2.2]|}%c|c|c|c|c|c|c|c|c|c|c|c|c|}
 \hline
 \thead{taxa de\\ amostragem} &\thead{duração da\\ amostra (ms)} & {\thead{tamanho\\ do bloco}} & {\thead{duração\\ do bloco (ms)}} \\
\hline
 \multirowthead{4} {\SI{44.1}{\kHz}} & \multirowcell{4}{ 0.0226} & 128 & 2.90 \\
 & & 256 & 5.80\\
 & & 512 & 11.60 \\
  & & 1024 & 23.21 \\
 \hline
 \multirowthead{4}{\SI{48}{\kHz}} & \multirowcell{4}{ 0.0208} & 128 & 2.66 \\
 & & 256 & 5.33 \\
 & & 512 & 10.66 \\
  & & 1024 & 21.33 \\
 \hline
 \multirowthead{4}{\SI{96}{\kHz}} & \multirowcell{4}{0.0104} & 128 & 1.33 \\
  & & 256 & 2.66 \\
   & & 512 & 5.33 \\
  & & 1024 & 10.66\\%128 & 256 & 512 & 1024 & 128 & 256 & 512 & 1024 \\
 \hline
 \multirowthead{4}{\SI{192}{\kHz}} & \multirowcell{4}{0.0052} & 128 & 0.66 \\
  & & 256 & 1.33 \\
   & & 512 & 2.66 \\
  & & 1024 & 5.33 \\%
 \hline
 \end{tabular}
 \end{center}

 \end{document}