Download Master problem with multiple torrents

[infamous_pb]

I have been using the Download Master utility to download torrents without any problems. However, if I have it download two or more torrents at the same time, the USB HDD will eventually disconnect and then reconnect (after about a minute) and then it will keep sporadically doing this again. Any reason why Download Master would have problems with more than one torrent going on at the same time?

Asus rt-n66u Firmware Version:3.0.0.4.260
Download Master: ver. 3.1.0.70
Seagate Expansion Desktop External Hard Drive - 2TB USB 3.0 (SRD00F2)

Thanks