Just to add a bit more info on this topic... as it has affected myself as well...
the target ftpd has always been either g6 or bulletproof-ftpd... they are one and the same.... i receive this error sending from raidenftpd, glftpd, serv-u...
I first noticed this problem in 1.4 (can't remember the build), and noticed it in every subsequent build... and even with the 2.0 version and all release candidates...
I believe that the first few bytes of the transfer are neglected or not sent for some reason... when transferring a WinRar archive.... i cannot open it and the header seems incomplete... that and the fact that resuming the file leads to corruption is why i believe the above is true.
It only happens if transferring in the alternate-fxp mode.... or non-pasv mode. The file sizes transferred were 15,000,000 5,000,000 and 1.44 mb (zip files).
I am behind a linksys router, am the dmz host. The target ftpd was always behind a router or firewall of some sort... it also appears that for the source ftpd, it does not matter whether a firewall or router was used as the corruption happened regardless...
Your findings may be different, but that is how this bug affects me... hope any of this info helps...
on a totally unrelated note.... i thought this only happened to me lol