I know Mr. King frowns upon us tampering with the "new blog post" line, however I think twitter-tools.php self-destructing (whether intentionally or unintentionally) is a bit excessive. :)
I've tried to edit that line on two occasions, on two different blogs, via the WP admin panel. Both times as soon as I click "Update File" (even if I don't change anything) the file's contents disappears, as does TT from my plugins list. It seems the only way I can safely edit the file is through cpanel.
I don't have this problem with any of the other plugins I use.