This can happen during a loading or unloading operation and a jammed cassette can cause it, however if none of the above applies try lightly pressing on the top of the cassette loading tray, or alternatively have a try at this non technical procedure which sometimes get things working again in more than just JVC branded equipment, the procedure being to jolt the bottom of the camcorder in the palm of your hand, the reason for doing this being that electro-mechanical camcorders use position sensors in various places and sometimes although the mechanism looks to be fully home, electrically it isn't! and the jolt can on some occasions correct this problem. However E-01 can also indicate more dastardly reasons like a cog having jumped a notch on a timing wheel, this necessitating case dismantling to investigate the cause, or other electronic defects of a nature too detailed to explain using this box.

my unit is GR D73U, same problem with yours. Is your problem fixed? how did u do it, pls help tnx!