Per the Nav Menu Roles FAQ:
I don’t see the Nav Menu Roles options in the admin menu items?
This is likely because you have another plugin (or theme) that is also trying to alter the same code that creates the Menu section in the admin. For example, the UberMenu Mega Menus plugin is a known conflict with Nav Menu Roles.
This is not a failure of Nav Menu Roles and there isn’t anything I can do about it. WordPress does not have sufficient hooks in this area of the admin and until they do plugins are forced to replace everything via custom admin menu Walker, of which there can be only one. Until these hooks are added the menu modification plugins are unfortunately going to conflict with one another.
There’s a possibility this will be added in WordPress 3.6 http://core.trac.wordpress.org/ticket/18584
This isn’t a failure of Nav Menu Images either. There is nothing either of us can do until the proper hooks are added in the core. That obviously didn’t happen in 3.6 as there’s apparently a serious issue with a limit on the data being saved in the menu section that is holding everything up. I cannot say when/if it will be resolved.
