Lead Actor Swapper script error

[Ace_V]

And that's hoping there's no such issue as a NilClass error message because Game_System never owned any lead_actor method or @lead_actor being set to nil (the default value)...

So Ace_V, was there any specific error message mentioned in your popup window or backtrace script? Can you post it here as is?
It's just to make sure nobody is skipping or ignoring any vital details here...

Hi, kyonides and DerVVulfman!

Here's the error that is displayed.  

   

EDIT: I also tried both of DerVVulfman's suggestions (I spotted the slipknog typo and changed it to slipknot) but kept getting errors regarding $game_system.lead_actor:
Script 'Lead Actor Swapper' line 66: NoMethodError occurred. Undefined method '<' for nil:NilClass
I guess it doesn't recognize this?    $game_system.lead_actor 0 if $game_system.lead_actor < 0