Post Body Content Missing & Category Pages 404

I installed AT3.4.6 on one site, then decided the domain name should be different, and so reinstalled on site 2. (www.personal-authenticity-project.com). I manually reinstalled the plugins and their settings. I exported the posts from site 1 and imported them to 2.

Except for my top post on my home page, the following posts correctly show title, excerpt, and footer. HOWEVER, when I link to the excerpted post's page, the post's body content is missing. The title, byline, and footer show, but not the post body content.

When I go to "edit posts", the posts has full content, but when I preview, no body content shows. I thought of trying to re-post (copy the content to a new post and preview), and this new post preview also showed no body content, although there's full text in the edit area.

Researching this on the web, I saw one site suggest testing whether the problem occurs with the default WP theme. It does not occur with the WP default theme (matter of fact, all of the posts on the home page show full content, they are not excerpted).

With regard to categories, neither AT nor the default theme show category content. Instead, there's a 404...

Is there any help you can provide??? Thanks in advance for any suggestions.