Originally Posted by munki

Make sure your FTP client supports file resuming, make sure the feature is turned on... check if you are uploading in binary mode... may fuck up some things, but typically doesn't have an effect on containered videos such as flvs/f4vs. If it's still not working, since it appears you are outputting to an flv that is basically just a wrapper for an mp4, try direct uploading an mp4 version which should work with same players, and see if that corrects issues.