\documentclass[10pt,a4paper]{article}

\usepackage[cp1250]{inputenc}
\usepackage{czech,a4wide}
\usepackage{fancyvrb}
\usepackage{gnuplottex}

\begin{document}

  A

  \begin{gnuplot}
    plot sin(x)
  \end{gnuplot}

\end{document}

