permalinks not working

Hi is there anyone out there that can tell me why my customized permalink structure is not working, wordpress is updating my htaccess file automatically, but any structure I try to implement does not work except the wordpress default I keep getting 404 message now the particular article is in my catergories,archives and posts but cant get to single post page through the permalink except the default structure

if any one knows how to fix please let me know
Thanks Steve