What happens when you INDIVIDUALLY connect each drive to the AE? What happens when you connect ONLY THE HUB? Assuming the hub doesn't kill the AE, what happens as you add each drive? At some point in there, your complex setup is somehow introducing a glitch. It may be the number of drives, the hub, the mix of drives, which ports on the hub they're connected to, or something else. However, I don't think Apple envisioned the AE being host to a few terabytes of USB drive while also performing network functions...