A "Disk Error" when loading styles usually means that there is not enough user style memory left. This usually occurs when loading to User Styles #2 & #3. Loading to User Style #1 usually works.

It has been reported, that the keyboard could actually reset it self, when playing loudly, especially when there is much of bass.

It is believed to be a shortage of electricity due to a too small power supply. At least 2 amps power is required.