In the following code, the command \label{my} appears on page 4, as well \pageref{my} says "4", but the hyperlink points to the page one. Why is that?
\documentclass{book}
\usepackage{hyperref}
\usepackage{lipsum}
\begin{document}
% Four pages of text.
\lipsum[1-20]
% The label is on fourth page.
\label{my}
% Buggy pageref. It produces the number 4, but the link leads to the first page.
\pageref{my}
\end{document}
\labelcommand attaches a marker to the nearest structure -- \section, \caption, etc -- that can receive an anchor. Your document has no anchorable structures at all; hence the default anchor, the start of the document, applies. Use the \pantomsection command to create additional anchors for \label commands. – Mico Mar 23 '12 at 03:05