I've got similar problems under OS X Mojave.
What I did so far to get it sorted:
#1 Created a new user named "Toast"
#2 Booted into user "Toast"
#3 Installed "EasyFind" by DEVONtechnologies (it's free)
#4 Searched for all files and folder in the user-folder of user "Toast" containing Toast and or Roxio + deleted them all
#5 Re-installed Toast 19 Pro - BD mastering now works as long as I do not try to include a standard BD menu - if adding a a BD menu I have to disable all 4 menu options (Include scene menus etc)