What hub are you using?
Pi does not work with usb3 hubs,
usb 2 hubs are low on power for erupters. Even the best with 2500mA psu only stay stable with 5 erupters.(D-Link 7 port is one of the better units, and falls over with 6 erupters in my rig)
Pi usb support is not the best. I have better results by only using one port on the Pi. So move the BFL to the hub.
Try another hub. or add another hub in daisy chain.
EDIT see my post from yesterday
Hub brand escapes me at the moment, like i said, not at home right now. But i do have the D-link 7 port hub being delivered today. I had also tried a 2nd powered hub daisy chained and it still crashed. But this is with cgminer. I understand the importance of the hub and such, but even if we assume the hub itself is having issues, then why doesnt bfgminer see my BFL which is plugged directly in? I think if i could find the answer to that then i could fumble through the rest.