As an NES but not a teacher, I believe there could be a slight difference:
1- I come here in order not to meet him - I've gone somewhere else, to avoid meeting him.
2- I come here not to meet him - I came here to see him perform [in the theatre] but not specifically to meet him.
The above sentences are my teacher's, not mine. Below is his explanation.
#1 means that I avoid meeting him or I don't want to meet him.
#2 means that my purpose is to do something else.
I am wondering whether the explanation is right.