Data I/O UniSite-xpi User Manual page 337

Additional Information
UniSite-xpi User Manual
The "Device insertion error" message can only be caused by a failure of
the continuity check. The continuity check is activated prior to device
programming. During the continuity check, the programmer applies
low level current to each pin on the device to determine whether it is
making good contact with the programming fixture.
After you disable the continuity test, we suggest you load a device
rather than program one. A load operation is less apt to harm the device
because no programming voltages are applied. Attempts to program a
device that is not making proper contact may result in overcurrent or
programming errors which may damage the device.
7. Messages
7-41