Serendipity 1.4 just went beta! That means my new upload validation code comes into play.
I developed the code a while ago, when people on the forums were having trouble with corrupted uploads. Some clients were uploading everything in ASCII mode, some were skipping files... it was a nightmare.
The new validation is working, but as more people start testing it, we expect to find the edge cases. Like the installation problem reported on the forum.
Turned out the FTP server was stripping all the linefeeds out of a weird file. I made a PHP application to check your FTP client and server for hiccups like the one that hit rj. You should be able to just unzip it and upload the files to your server; when you visit sumcheck.php, it'll explain what you should be seeing. You can let me know on the forums (or in the comments) if you find anything interesting.