I have so far not been able to reproduce this on any of my test machines, including a MacMini3,1 (the original Mac mini Server in my case). What I tested:

- installed OS X 10.10, install RB and driver, upgrade to 10.11 -> works 
- installed OS X 10.11, install RB and driver, reboot -> works

Can you send me a copy of the crash log (or a screenshot, or a photo), so I can go through the backtrace (felix . schwarz @ iospirit)?

Did you upgrade from a previous OS X release - or was this a fresh install?

How did you install Remote Buddy's driver? Through the Setup Wizard, through the Candelair preferences pane - or manually?

Does this only occur when booting in Safe Mode - or always?

Thanks in advance.

Best regards, 
Felix Schwarz