While building my next space platfrorm, I got this issue, by removing the radar from the platform.
The mod D.A.R.T. (1.0.7) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event dart::Custom event (ID 380)
dart/scripts/gui/dart-gui.lua:82: attempt to index field 'elems' (a nil value)
stack traceback:
dart/scripts/gui/dart-gui.lua:82: in function 'handler'
core/lualib/event_handler.lua:47: in function <core/lualib/event_handler.lua:45>
stack traceback:
[C]: in function 'raise_event'
dart/scripts/dart.lua:658: in function 'raiseDartComponentEvent'
dart/scripts/dart.lua:742: in function 'raiseDartComponentRemoved'
dart/scripts/dart.lua:753: in function 'func'
dart/scripts/dart.lua:797: in function <dart/scripts/dart.lua:792>

Wasn't able to reproduce it yet, so I am not sure whether an obvious simple solution I see would be sufficient.

Do you remember the steps you did before deleting the radar?

Not directyl, but by loading the game, it works.
Will keep a eye out, if this is happening again.

Just published V 1.0.8 which fixes several related problems I became aware of when looking for your issue. There is a good chance that yours is fixed too - as a fundamental mishandling with the different parts of the GUIs was fixed.

But as long we don't know the exact way to it, it isn't sure

So, I still have this issue of a crash by deconstruction. Here is a save, with only the bare minimum (Space Age + D.A.R.T)
https://drive.google.com/file/d/1eSdRMC6m8m1Z4nrXx7GPA-0ZUwbo-Nxq/view?usp=sharing
Delete the radar on "Dr. Who" (Last Platform) and you will see a new issue:
The mod D.A.R.T. (1.0.10) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event dart::on_space_platform_mined_entity (ID 73)
dart/scripts/dart.lua:756: attempt to index field 'entity' (a nil value)
stack traceback:
dart/scripts/dart.lua:756: in function 'func'
dart/scripts/dart.lua:813: in function <dart/scripts/dart.lua:808>

Loading your save fails 🙁

82.278 Error AppManagerStates.cpp:1662: Kartenversion 2.0.58-1 kann nicht geladen werden, weil sie höher als die Spielversion (2.0.55-0) ist.

But after inspecting my code I have an idea, what's going wrong. But at the moment I've no idea how this (unwanted) state which causes the crash could be reached. Do you remember how you built the radar (normally, using a blueprint, copying ,...)?

Okay, I use the experimental version, as I had some issues with my BP. upps 😅

About the radar, normally. Please select it from the menu and place it down. As I have reworked the ship with new techs.

Really strange. Switched to the factorio beta and could reproduce this, but only with your save file - with my own save files this doesn't happen 😏

But the good news - found some workaround. If you open the fcc (once) before trying to delete the radar, the crash doesn't happen. Need some time to dig deeper, to see what's really going wrong there

a new release with the fix for this bug is online