Problem solved, though I still don’t know why.
Since JuliaPro 1.01.1 was crashing, I tried the standard Julia 1.01.1. I could run julia.exe without crashing, but when I tried to add any package, “ERROR: no active project” would show up and operation would fail.
I searched this error message online and found this post:
Since JULIA_LOAD_PATH was mentioned in this post, and on this machine I had JULIA_LOAD_PATH pointing to 2 paths where I created my own modules, I tried removing the JULIA_LOAD_PATH environmental variable.
After that, magically the Julia package adding started working. I then tried re-installing JuliaPro 1.01.1, and it also worked!
I still don’t know why. On another Windows 10 64-bit machine I also had JULIA_LOAD_PATH pointing to similar paths, but that machine had no problem with JuliaPro.
Anyway, I’m happy it’s working now.