Solve a "possible conflict" detected by Nav Menu Rules

This message appears on a site:

Nav Menu Roles has detected a possible conflict with the following functions or classes: ClientDash_Core_Page_Settings_Tab_Menus. Please see the FAQ for more information and possible resolution.

Here is the FAQ url:

It doesn’t cover the error message or have a link to another site for further notes/details.

The functionality needed is to create two new roles so that a small group of non-technical users can add/modify users, and another group of more technically advanced users have access to other backend capabilities, and then restrict other Dashboard-level access.

Except for these messages which are cryptic and point to a potential instability, Nav Menu Roles does the job.

If you can help resolve the warning message, that would be terrific.

If you can recommend another plugin to do the job at least as well, that would also be very welcome.

Thanks in advance!