tp/downloader: bad behavior setting speed limit

[barbara.xxx1975]

port version:
# $FreeBSD: ports/ftp/downloader/Makefile,v 1.57 2005/09/09 18:26:15 lawrance Exp $
(but also seen in at least the two previous versions)

If I set the speed limit to 'Low' or 'Medium' the program starts to behave badly.
It seems, as I can see in the program log window, that it sends truncated request string to the server and it get a lot of 'bad request' or get disconnected after few bytes.
This behaviour stops, and the program starts to work correctly, as soon as I set the limit to 'Unlimited'.

uname -v
FreeBSD 5.4-STABLE #0: Mon Sep 12 00:53:00 CEST 2005     root@:/usr/obj/usr/src/sys/DAEMONETTE