multiple channels recording error!!

my cubase 6.5 gives the error with recording
it makes no different how much recording channels there are active
it will give random this error : to much recording channels and stops recording.
my laptop is a dell fostro 3550
soundcard motu ultra light latest updates
interface : dawicontrol dc-1394 ecard firewire.
window 7 64 bit pro.
cubase 6.5 latest update
please advise .
with regards