FTP Through Explorer Strips Content Of Some Files

I am having a weird problem when I try to ftp files through explorer - certain files are completely stripped of their content. I've attached some sample files to this message. The files that start with "doesnt_work" will get stripped when copied over ftp. The files that start with "works" will not get stripped. The only difference between the works and doesn’t_work is that I have removed some of the content for the works version.

Some facts:All the files are plain text. I've verified that this happens on multiple ftp servers. It happens regardless of the file extension. I've turned off antivirus and netnanny software and it still happens. If I use another ftp client such as CoreFTP lite, or ftp.exe from the command line, it doesn't happen- all files transfer properly This also happens with explorer-ftp transfers on windows XP.