Okay... that is incredibly scary. I can't believe this is release candidate software. I get bizarre screen redraw issues, preferences for new users don't stick, sluggish Workgroup Mgr performance... Wow.
For those that have a working 10.1.5 server configuration, please think doubly hard about upgrading, especially if it's in a critical environment. I'm going to try wiping the server and reinstalling. Wish me luck.