i confirm this bug when i use these 5 links in same time:
<ftp://speedtest1.dyndns.org/image.iso>
<ftp://speedtest2.dyndns.org/image.iso>
<ftp://speedtest3.dyndns.org/image.iso>
<ftp://speedtest4.dyndns.org/image.iso>
<ftp://speedtest5.dyndns.org/image.iso>