Ok, this is strange. It seems that all files bigger than 64k downloaded through apache2 get corrupted somehow. It's always the same — on every 64k boundary there is about 5.7k of data from the start of the file.
Can someone please confirm this? I've tested it from all HTTP clients I have, even tried disabling my firewall, searched for funny processes, viruses etc. Nothing so far. I'm using xampp-win32-1.5.1 on Windows XP SP2.
It doesn't happen on my old PHPTriad.