Permalink as page name, 404 error

Hi!

I’ve looked through quite a few related posts but not really found a solution to my problem. Basically I want to set up permalinks for my blog pages so they look like this: http://mysitename.com/blog/pagename but when I do this, I get a 404 error. I’ve tried setting up a .htaccess file but that hasn’t worked. I tried using /%pagename and /%postname but those haven’t worked either.

Any help would be gratefully received. Thank you.