There have been a couple of reports of problems, see
Who Will be First to Get theirs???. All I can suggest is trying a different cable and/or a different USB port. Since you are seeing this on two computers, you may have to send the Pocket Pro back.
I have had no major problems once I switched to the provided USB cable, however I sometimes have to remove and reconnect the USB cable to get the Pocket Pro to recognize that there is a computer connected (rather than a power-only connection). My laptop is relatively old, but the Pocket Pro's USB does seem more flaky than that on the EZ Reader Basic.