[kh99]

Could you try replacing the code in the "PM Quote Formatting - Add CSS" plugin with this:

if (THIS_SCRIPT == 'private' && $vbulletin->options['kh99_pmq_enable'])
{
    if (intval($vbulletin->versionnumber) == 4)
    {
        if ($vbulletin->options['storecssasfile'])
        {
            $template_hook['headinclude_css'] .= '<link rel="stylesheet" type="text/css" href="' . vB_Template::fetch_css_path() . 'kh99_pm_quote.css?d=' . $style['dateline'] . '" />';
        }
        else
        {
            $template_hook['headinclude_css'] .= '<link rel="stylesheet" type="text/css" href="' . vB_Template::fetch_css_path() . 'kh99_pm_quote.css" />';
        }
    }
    else // vb3
    {
        eval('$kh99_pmq_css = "' . fetch_template('kh99_pm_quote.css') . '";');
        if ($kh99_pmq_css !== '')
        {
            $vbulletin->templatecache['headinclude'] .= '<style type=\"text/css\">' . addslashes($kh99_pmq_css) . '</style>\n\n';
        }
    }
}