BTW I tried "universal usb installer" (which directly supports BT5) and I get the same result, so the problem isn't unetbootin specific. I am curious, has anybody out there been able to boot to gnome...

I'm having this same problem, getting operating system not found. I don't have a DVD drive to burn with. I downloaded the iso via torrent and the md5/sha1 both seem authentic:

BT5-GNOME-64.iso...

Not supported out of the box, however the driver found here works fine in BT4 R1.

Monitoring supported
Packet injection NOT supported (driver is open source though, if anybody wants to add it...)

What kind of wifi setup gets you 10 miles?

From what I am reading here, the AWUS036NH doesn't support packet injection.

For various reasons I can't reformat/repartition the hard disk on the laptop I am using (mainly there's just not enough room on its 64GB SSD) so I am using backtrace via a bootable USB stick.
...