I accidentally mixed up the sequence, entered the /S command at the start and got a critical error

Error while running event MegaPackFactory::on_console_command (ID 74)
MegaPackFactory/control.lua:196: attempt to index local 'area' (a nil value)
stack traceback:
MegaPackFactory/control.lua:196: in function 'Start_monitor'
MegaPackFactory/control.lua:674: in function <MegaPackFactory/control.lua:657>

Could you try the new version? If it crash again please upload the new crash info so I can try to fix it.

The same. Maybe just make a menu where only a certain sequence of actions is possible.

Error while running event MegaPackFactory::on_console_command (ID 74)
MegaPackFactory/control.lua:199: attempt to index local 'area' (a nil value)
stack traceback:
MegaPackFactory/control.lua:199: in function 'Start_monitor'
MegaPackFactory/control.lua:764: in function <MegaPackFactory/control.lua:747>

also an error if you just type /E

Error while running event MegaPackFactory::on_console_command (ID 74)
MegaPackFactory/control.lua:406: attempt to index local 'area' (a nil value)
stack traceback:
MegaPackFactory/control.lua:406: in function 'End_monitor'
MegaPackFactory/control.lua:769: in function <MegaPackFactory/control.lua:747>

adn /P
Error while running event MegaPackFactory::on_console_command (ID 74)
MegaPackFactory/control.lua:618: attempt to index local 'area' (a nil value)
stack traceback:
MegaPackFactory/control.lua:618: in function 'place_a_MPF_with_monitor_data'
MegaPackFactory/control.lua:773: in function <MegaPackFactory/control.lua:747>

I also realized that the /M1 /M2 /M3 command can be canceled by re-entering it. But I don't understand if the allocation of territory can be completely canceled

Yes, you have to do that in order. I think I will fix the crash next version. There is no side effect if you re enter the Mark command. When you enter /S all the record is initiled. So you can restart the process without losing anything.