For those who are familiar with my other posts regarding the problems I was having with the Pocket Pro, here's an update.
My new/replacement unit arrived yesterday. So far so good.
After charging for 12-hours (overnight), I uploaded (old) firmware, set the clock (although the '5' button was a little tempermental), uploaded a couple of ebooks (pdf and epub format) and both opened without a hitch.
Haven't taken the time to actually sit down and read anything, so I'll know more about other features as I come to them.
Keeping my fingers crossed that third time is a charm.
Public thank you to Astak Support and Robertb for all your help.