My internet went down last week; now it's back. Thanks for attempting to replicate the problem for me. While the test blog is now showing up in the team streams, my other blog is still missing. Since I have made any changes to the way my Sparkpage is viewed (I mentioned that in my original post), I'm going to chalk up this error to the fact that I posted that blog Tuesday night, which is when Spark does its weekly maintenance. I'm assuming that since the site wasn't running as usual, this error occurred. Is that a valid assumption?
Thanks for all your help Kelly!