The most likely cause is the current AA batteries just don't have enough power to process the USB Export from the device.

RECOMMENDATION

1. Remove the current AA batteries from the Receiver (the unit with Micro USB port on the side)

2. Leave the Receiver without AA batteries for at least 5 minutes (don't worry, the button battery on the circuit-board keeps enough power to retain memory)

3. After at least 5 minutes or more, insert a fresh set of good quality AA batteries (not rechargeable types)

4. When inserting the second battery, observe the LED on the circuit-board. It must flash RED then GREEN. (if it does not, re-try inserting the AA batteries)

5. Re-try the export to USB stick again.