One of my PowerCD was not working and just showing the "ERR" fault code.
Was not able to see anything obvious inside, but was confident the problem was in the motor area (was unable to hear the motor spin)
To cut a long story short, the spinning motor was unable to spin.
the disk is just drop in the PowerCD, not pushed like any other CD-Rom, so probably someone tried this method, jamming it for good.
lifting a little the center grey disk solved the issue.