@CSL - I'm adding more debugging on the next release, so we can see what's keeping the MKIV from picking up the CD changer. LED's will be handled in a separate process to improve notification.
As for navcoder, I use it all the time - just set your Kracker to diagnostic mode. When you open Navcoder, select the Com port the Kracker is on. I've used it from the ibus (trunk) and OBDC.