Ok...I changed the admin settings for User Profile/Registration Page from my DR reg page to None Specified and I am now able to create a new page and add the Users & Roles admin module to a page. Also, my earlier pages that I added the module to are now directing properly and I see the Users & Roles admin module on those pages where I originally added it.
So...what has changed? The user profile/reg page has always been set to my custom DR page since I installed and configured the module. I have no registration user controls in my skins as I only provide links via urls to various registration pages within my siite. If I have need to add a registration user control to a skin in the future and need it to direct to a custom registration page, wouldn't I then have to set the user profile/regitration page to this custom page and hence wouldn't the issue return?
Have I misunderstood from the beginning the way the DR modue should be configured with the admin user profile/reg settings?