Constantly restarting, never fully finished uploads

Hello all!
 
So I'm trying to upload a fairly large (800 MB) file to Lulu.com (a self-publishing site; their limit is 2 GB) via SmartFTP, which is their recommended method for larger files.  The file uploads slowly--the estimated time left when it starts is usually a bit over an hour--which I wouldn't mind so much except that it never finishes uploading.  It gets to maybe 99% and then suddenly restarts.  It has put several copies of the files in my Lulu files folder, but they're all corrupted and can't be opened.
 
My computer generally doesn't have any problems with internet speed, or speed as a whole.  The current upload speed in SmartFTP is 256 KB/s, and the dialog is as follows:
 
[09:34:46] SmartFTP v5.0.1344.0
[09:34:46] Resolving host name "ftpupload.lulu.com"
[09:34:46] Connecting to 216.27.62.242 Port: 21
[09:34:46] Connected to ftpupload.lulu.com.
[09:34:46] 220---------- Welcome to Pure-FTPd [privsep] ----------
[09:34:46] 220-You are user number 1 of 50 allowed.
[09:34:46] 220-Local time is now 09:34. Server port: 21.
[09:34:46] 220-This is a private system - No anonymous login
[09:34:46] 220-IPv6 connections are also welcome on this server.
[09:34:46] 220 You will be disconnected after 15 minutes of inactivity.
[09:34:46] USER ((my email address))
[09:34:46] 331 User ((my email address)) OK. Password required
[09:34:46] PASS (hidden)
[09:34:47] 230-User ((my email address)) has group access to:  ftp     
[09:34:47] 230 OK. Current restricted directory is /
[09:34:47] SYST
[09:34:47] 215 UNIX Type: L8
[09:34:47] Detected Server Type: UNIX
[09:34:47] RTT: 45.621 ms
[09:34:47] FEAT
[09:34:47] 211-Extensions supported:
[09:34:47]  IDLE
[09:34:47]  MDTM
[09:34:47]  SIZE
[09:34:47]  REST STREAM
[09:34:47]  MLST type*;size*;sizd*;modify*;UNIX.mode*;UNIX.uid*;UNIX.gid*;unique*;
[09:34:47]  MLSD
[09:34:47]  ESTP
[09:34:47]  PASV
[09:34:47]  SPSV
[09:34:47]  ESTA
[09:34:47] 211 End.
[09:34:47] PWD
[09:34:47] 257 "/" is your current location
[09:34:56] MLST LPFOS_full.pdf
[09:34:57] 550 Can't check for file existence
[09:34:57] TYPE I
[09:34:57] 200 TYPE is now 8-bit binary
[09:34:57] SIZE LPFOS_full.pdf
[09:34:57] 550 Can't check for file existence
[09:34:57] MDTM LPFOS_full.pdf
[09:34:57] 550 Can't check for file existence
[09:34:57] STAT LPFOS_full.pdf
[09:34:57] 213-STAT
[09:34:57] 213 End.
[09:34:57] CWD /LPFOS_full.pdf
[09:34:57] 550 Can't change directory to /LPFOS_full.pdf: No such file or directory
[09:34:57] The operation has been added to the Transfer Queue. Start the Transfer Queue to process it.
[09:35:27] NOOP
[09:35:27] 200 Zzz...

menu: Help->Request Support

I have the free version, so I was hoping for fellow users to provide feedback...