After some troubleshooting trying to setup a NPrinting 17.2 environment for practice, I was hitting the wall with a connection failure to a local Qlikview Document (QVW File).
The following error in the nprinting scheduler log gave me clue for some component missing :
"Could not load file or assembly 'Engine.Navigator.QlikView, Version=22.214.171.124, Culture=neutral, PublicKeyToken=aa3e5cc00a2bd1f0' or one of its dependencies."
After some time spent searching the internet for a solution for the error, I realized that Qlikview Desktop 32 bits version was installed, instead of the 64 bits.
NPrinting was failing to connect to a local Qlikview Document (QVW File) because it could not find the 64 bits dll of Qlikview Desktop in the registry.
Conclusion: When installing NPrinting 17 engine Server check if the 64 bits version of Qlikview Desktop is installed or you have the correct installer because NPrinting 17 runs only in 64 bits.