Cannot add new Page since upgrade

Upgraded a client’s WordPress site to 2.8.5 and while everything else seems to be working, she can no longer add a new Page.

You can add new Posts, new Categories and new Links. But when a new Page is created, clicking on the link to it results in a 404 Page Not Found error. This happens whether the link is in the WP-Admin (view this page) or the site menu. All of the older Pages are fine; the links to them continue to work. It is only links to the new Pages, the ones added after the upgrade, that result in the 404 Error.

I have just tested adding a new Page and confirmed that it does appear in the MySQl database and that the post_name field is correct and the guid is listed as: http://secondchancedream.com/?page_id=379.

I’ve tried to the tips like deleting the .htaccess file which completely screwed up the 404 direction (it used the hosting services default 404). This installation is in a sub-directory with the add-on domain name pointing to the sub-directory. Again, my confusion comes because the *only* thing that seems to be affected are new Pages.

Any other suggestions or help would be greatly appreciated since the client is in her 60’s and driving me nuts (she’s a New Age therapist…).

Thanks!