I have a BUE installation and am backing up data from an Iomega StoreCentre NAS.
Its a cheap device and I am unable to install an agent onto this device.
Every night when I backup, I received error;
You would just have to live with this error message because you would not be able to install an agent. Just ignore it.
However, do note that you still need to buy a RAWS agent to back up this NAS, although you cannot install the agent on it. This is to comply with licencing terms.