I forgot to past here also the IE8 status bar message
Message: ‘e’ is null or not an object
Line: 246
Char: 1320
Code: 0
URI: http://dev.webbissimo.info/wp-admin/load-scripts.php?c=0&load%5B%5D=hoverIntent,common,admin-bar,svg-painter,heartbeat,wp-auth-check,shortcode,media-editor,media-audiovideo,wp-playlist,mce-view,im&load%5B%5D=gareaselect,image-edit,thickbox&ver=4.0
hope this could help better your investigation
Regards
