You may get the error that you're getting if there's a problem with the USB port of the computer, with the USB cable, or with the USB port of the device itself.
Try connecting the Samsung mp3 device to a different USB port of your computer. Usually, it's best to connect the device on the USB port at the back of the computer. Make sure that the USB cable is properly inserted on the USB port of the device and on the computer.
You may also try connecting the Samsung mp3 device to a different computer to isolate the problem.
Another isolation is to try connecting a different USB device on the computer, just to check if the USB ports of the computer is working properly.
Try using a different USB cable also, if you have any.
For more help:
http://www.supportrix.com