After install and reinstall keep getting nd cfg error - cannot bring up flight book and FMC works sometimes

I had great expectation for this plane and like the a320 it turned out to be an expensive disappointment

Interesting. Both aircraft installed and worked terrific for me and a great many others that I know personally, and I used both aircraft for hundreds of hours before I switched to MSFS.  Not only that, but they worked with 100+ addons I had in P3Dv4 and P3Dv5.

 

It might be in your interest to ask for tech support, the team here is pretty darned awesome!  If you do that, I recommend providing some detailed system specs, what other complex addons you have that are working and if you had any issues with other complex addons. I would also add if you're running any type of computer security, if you disabled the security during the install process, if you've excluded the various flight sim installation folders from security scans, and if you're running P3D "As Admin".

 

My very best wishes to you!