|If you are saying that the exact same setup has worked correctly in the past then there might be an issue with the camera.|
Normally your usb hub has to be a "powered" type to support all usb products. If your hub doesn't have an external ac power adapter then you might try one with an adapter.
You can connect the camera to the computers usb port and find how much current it is drawing. If the computers port does this same power issue then your camera is going bad.
This has nothing to do with software.
Playing to the angels
Les Paul (1915-2009)