Hi,
I haven't tested the non-local dispersion corrections, but just few comments based on the manual:
1) For geometry optimizations you should only use the self-consistent formulation to obtain the gradients ($doscnl). But probably this is not the issue since you have tested this option, too.
2) The non-local dispersion corrections have only been implemented for ridft and rdgrad, so you need to run jobex -ri to make them work. How did you run jobex?
Best,
Antti