After running fine with zero issues forever, I'm now getting a ZOMBIE status in cgminer with the following error displayed in the console:
ERR: Asked to memcpy 0 bytes from usbutils.c _usb_read(): 3075
HFA: OP_USB_INIT failed! Operation status 20 (Regulator programming error)
I've tried cycling power, restarting, doesnt seem to help.
Any ideas?

Any time I've seen that error it was a loose or disco'd power connector or the PSU wasn't turned on. Have you tried a different supply?