As usual, I try to solve a s/w problem to no avail, I then post my problem to some forum like this for help. Then I solve it almost immediately thereafter.
My problem was on this step:
>>> envipyengine.config.set('engine',
)
I took to mean the path to my bin directory:
C:\\Program Files\\Harris\\ENVI55\\IDL87\\bin\\bin.x86_64
Instead, I had to point the engine path to the actual executable:
C:\\Program Files\\Harris\\ENVI55\\IDL87\\bin\\bin.x86_64\\taskengine.exe
Problem solved