Biblatex with classicthesis. \bibhang already defined

I've an issue with the bibliography in classicthesis. My main.tex:

\documentclass{scrreprt}

\usepackage[english]{babel}
\usepackage[babel]{csquotes}
\usepackage[style=numeric]{biblatex}

\usepackage{myclassicthesis-preamble}
\usepackage{classicthesis}

\bibliography{references}

\begin{document}
Text
\end{document}

My references.bib:

@manual{label,
author= {myauth},
editor= {myedit},
title=  {mytitle},
date=   {2011}
}

Finally the error:

! LaTeX Error: Command \bibhang already defined.
Or name \end... illegal, see p.192 of the manual.
[...]
l.637 \newlength{\bibhang}
?

Problably there is something already defined in myclassicthesis-preamble, but I don't know what.

I use TeXworks in Windows 7 x64.

-
The package myclassicthesis-preamble loads natbib. See tex.stackexchange.com/questions/37076/… –  Joseph Wright Dec 6 '11 at 13:42
@JosephWright The question is the same, but the answer is not clear for me, sorry. –  Baduel Dec 6 '11 at 13:58
I'm not quite clear on where the special preamble file comes from. It seems to be a some settings which show off classicthesis, but which really are just part of the preamble and should simply be copied into place. –  Joseph Wright Dec 6 '11 at 17:26

The file myclassicthesis-preamble.sty loads natbib; if you are not going to use any of the features of natbib, open the file and comment out, or delete, the lines

\PassOptionsToPackage{square,numbers}{natbib}
\RequirePackage{natbib}                % NB: LyX likes to set natbib too, let's avoid clashes
-
Thanks, it works =) –  Baduel Dec 6 '11 at 14:44