@Caryn Goldsmith -

Incase anyone else runs into this with the Wordpress upgrade breaking the links. I just hit the same problem. Once I saw Caryn's comment about pretty permalinks, I tested one of the new shortlinks (which is essentially the defaults) and it worked correctly. With that in mind, I went Settings -> Permalinks and set the blog to Default. Then hard refreshed the front end and made sure everything worked (yes). Then I went back to Settings -> Permalinks and reset it to /%postname%/, and again hard refreshed the front end and it all worked. I assume this sets a rewrite rule in the htaccess that had somehow gotten jumbled. That fixed it. Hope this helps someone!

Kimberly