\documentclass[a4paper, oneside, 10pt]{article}
\usepackage[utf8x]{inputenc}
\usepackage[czech]{babel}
\usepackage[unicode]{hyperref}
\begin{document}

\url{http://xref.dokuwiki.org/reference/dokuwiki/inc/parserutils.php.source.html\#l99}

\section{\texorpdfstring{Headline}{Headline}}
\label{sec:headline}

\section{\texorpdfstring{Headline}{Headline}}
\label{sec:headline2}

%!!! RECURSION LOOP HAS BEEN PREVENTED !!!

\end{document}