sectsty

[Remzi Seker]

I have the preamble seen below.
I need to have the sec, subsec, etc numbers ending with a period like 1.1., 
1.1.1. etc... 
I tried the method proposed in the help file of sectsty but i get a lot of 
errors... I tried titlesec, but that gives me a lot of errors too. Any idea>

Remzi
-------------------------- my related preamble ---------------------
\usepackage{sectsty}

\chapterfont{\normalsize\mdseries\centering}

\newlength{\mySpaceUnder}
\newlength{\mySpaceOver}
\setlength{\mySpaceUnder}{0.5ex}  % 4cm as an example ;-)
\setlength{\mySpaceOver}{5ex}   % 3cm as an example

\renewcommand\section{\@startsection {section}{1}{\z@}%
                                   {\mySpaceOver}%
                                   {\mySpaceUnder}%
                                   {\normalfont\small\mdseries\centering}}

\renewcommand\subsection{\@startsection {subsection}{1}{\z@}%
                                   {\mySpaceOver}%
                                   {\mySpaceUnder}%
                                   {\normalfont\small\mdseries\textit}}


\renewcommand\subsubsection{%
    \@startsection{subsubsection}{3}{\z@}%
    {3.25ex \@plus1ex \@minus.2ex}%
    {-1em}%
    {\hspace{1cm}\normalsize\mdseries\itshape}%
}