I am a very green rookie of lisp but try loading selection and it will not bomb out.
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I'd do a couple of additional things,
SAVE the file before you attempt to load and run a command.
That way, if AutoCAD does lock up ( it's been known to happen ) you won't lose all your changes.
click DEBUG on the menu
Toggle
Break on Error to be true.
If the routine does 'Bomb' ( nerdy technical term) you can select Debug->
Last Break Source from the menu to see where the error was.
Check the code
Menu
Tools->Check code in editor This can save all sorts of grief.
Add a comment hyperlink address to the code source.