vsftp server shows some files not others
I've installed vsftp as ftp server on CentOS5. vsftpd.conf is unedited, works without change as it was installed (it's a private network on which I'm using anonymous ftp.)
For some reason vsftp will not serve some files which I downloaded from another system (using ftp.) The downloaded files simply don't show up at all if I come into vsftp via a browser, for example, and 'get' fails in a command-line ftp client. Other files originating from the local machine are served OK.
If I copy the downloaded file, vsftp shows the copy just fine but not the original; both files are in /var/ftp (the ftp server root.)
The downloaded file had group and owner as '65534' so I did chgrp/chown root, but that made no difference. Reboot makes no difference; restarting the client or using a different client machine makes no difference.
What am I missing or doing wrong? What doesn't vsftpd like about the downloaded files? This is happening on two separate machines, and I'm very puzzled.