There is a bug – in file syntaxhighlighter.php
Change: document.getElementsByTagName(“head”)[0].insertBefore( corecss, document.getElementById(“syntaxhighlighteranchor”) );
To: document.head.appendChild(corecss);
And: document.getElementsByTagName(“head”)[0].insertBefore( themecss, document.getElementById(“syntaxhighlighteranchor”) );
To: document.head.appendChild(themecss);