As of this morning, my site (http://www.clampants.com) was working fine and displaying correctly.

Suddenly, around noon, I noticed that my index page was blank...devoid of all posts (http://www.clampants.com/index.html). I've tried rebuilding the whole site multiple times, to no avail.

However, I can still publish posts, and they appear on their individual pages, such as:
http://www.clampants.com/archives/000426.html

...but the index simply contains no posts, and I can't fathom why.

Here is the code of my index template:
http://www.clampants.com/index.txt

(I've tried reverting the MTEntries code block to the Six Apart default here...to no avail)

Also, i'm running an old (!) install of MT (Movable Type 2.661). I've been meaning to upgrade forever (obviously), but everything was working fine up until this happened this morning. Would upgrading fix this, or just carry this problem over to the new install.

If anyone has any hints about this, it would be greatly appreciated...thanks!

Um. There's no MTEntries block in there?

Whoa, you're right...sorry about that. I've updated that text file to actually reflect my index template:
http://www.clampants.com/index.txt

So it seems i've figured out a fix (after agonizing over it all day).

Long story short, adding lastn="30" to the <MTEntries> tag...fixed things.

No idea why I suddenly needed to do that...I don't think I had that tag on my index before today and everything was fine....but, there you have it.

Check what you have in Entries to Display under Settings/General. That will affect how many days/entries worth are displayed on the index page if lastn isn't specified.