\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[latin1]{inputenc}
\usepackage[portuges]{babel}
\usepackage[pdftex,plainpages=false]{hyperref}
\usepackage{tabularx}

\title{Article title}

\begin{document}

The problem seems to be a quote character as the last non whitespace
character in a table title" :

\begin{table}[htbp]
\begin{center}
\begin{tabular}{l}\hline
\multicolumn{1}{|m{2cm}|}{\raggedright%
Table cell%
}\tabularnewline
\hline
\end{tabular}
\end{center}

\caption{Table "title" }
% this works: \caption{Table title }
\end{table}

\end{document}
