Where was the Roman Army in AD408?

[Nathan Ross]

Source? Never heard of that bit.

It's Zosimus, Book 5: "Affairs having thus been concerted [in AD410], the emperor called ten thousand Huns to his assistance in the war against Alaric."

Although this is from the antiquated online translation again, so it might need checking...

either a) there was no longer a strong military presence in northern Italy or b) they were there but refused to do anything.

Yes, that sounds about right!