Plugged in my Tascam US-122 directly into my MacBook Pro (OS X 10.6.8), rebooted in 32-bit mode (held keys 2 & 3 on my keyboard while re-booting)... and there came the green light on my US-122! No need for a powered USB hub.
Thanks for all your help! MacRumors Forum rock! ;o)
Thanks for all your help! MacRumors Forum rock! ;o)