With SU11 and latest SDK, saving with the Aircraft Editor an aircraft (for example after changed flight model parameters) it cleared Type and Name of many circuits in the system.cfg file
This is a really critical bug as it makes the aircraft no more working
Looks like the .cfg files are malformed,
Some of them have blanks (spaces) between the items, they are not needed.
Once you clear that you will be able to edit with the sim editor
(experience that in the electrical section)
I personally edit every CFG per hand and save them manually without using the Aircraft Editor. Its harder…but save and you also learn something