The preamble of
a LaTeX file is the part between the \documentclass
command and the \begin{document} command. LaTeX does not allow text in the preamble, you can only put definitions
and declarations there.
(2)
If you are still using LaTeX 2.09, replace the first
two lines by
\documentstyle[hyperlatex]{article}
(3)
For technical reasons the special input mode is
turned on by \topnode if you are using LaTeX2.09.