Okay, I solved the problem. Apparently I had removed and reinstalled some but not all of the packages Articles uses. After doing this, the blog articles page works.
Problem is now, when I click on the title of a post, it takes me to the article rendered in plain text, no HTML at all (I checked View Source). I suspect this has to do with Friendly URLs (the URL is www.mysite.com/articles.html/(date)/(of)/(article).
I'll keep looking, but if anyone knows what the problem is, I'd appreciate your input.
Thanks Again