save failed "800100"

when i download a game demo or a video file or a network update it will always say "save failed 800100"...etc. i have a psp version 3.51 and a 1gb memory stick duo with 456mb left and i have had my psp since '06 and this problem has never happened before,but i have been using a usb2.0 cable lately

Is this the full error code! if not please post the entire code!

800100-13 = Device / Media not found

8001xxxx = Libc error

Those 2 are the only 2 i know of that are near your code!