Unplug that Logitech wireless keyboard or mouse if you have it.

Those wireless USB dongles interfere with the HID interface that PEP1/2/3 need.

You mentioned this happens when trying to learn. What is the error mentioned when trying to download?

Next, have you tried using the firmware installer to do what is called a complete reset. There are steps somewhere here for 'complete firmware upgrade'.

Note that complete firmware upgrade will remove your current configuration from the device so be forewarned.