ever since i downloaded rockbox,theres been a problem hooking it up to my computer.everytime i hook it up,there is an error message that says that my usb device is unrecognizable and it is malfunctioning.when i go to explore to see if my ipod is there,it appears for like 5 seconds and then it closes.so i used my other usb,and the same message comes up.i know its not my usb,because itunes is able to read my ipod.what is the problem?