Thank you very much Toxaris, i managed to solve the first title error with your help.
For the blockquote error you'll find below the lines of the section0003 in my epub. I replace the copyrighted text by "TEXT" or TEXT :
<?xml version="1.0" encoding="utf-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<link href="../Styles/stylesheet.css" rel="stylesheet" type="text/css" />
<title>Epigraphes</title>
<style type="text/css">
/*<![CDATA[*/
@page { margin-bottom: 5.000000pt; margin-top: 5.000000pt; }
/*]]>*/
</style>
</head>
<body class="calibre">
<p class="sgc">« TEXT »</p>
<p class="sgc">TEXT</p>
<blockquote class="sgc1">
<p class="sgc2"><br class="calibre2" /></p>
</blockquote>
<blockquote class="sgc1"></blockquote>
<blockquote class="sgc1"></blockquote>
<div class="calibre4">
<span class="calibre5">« TEXT »<br class="calibre2" /></span>
</div>
<blockquote class="sgc1">
<div class="calibre6">
<span class="calibre5">TEXT</span>
</div>
</blockquote>
</body>
</html>
Many thanks,
Ibn