Assertion Failed

error: [string "[T] @libs/SpaceStation.lua"]:541: assertion failed!
stack traceback:
	[C]: in function 'assert'
	[string "[T] @libs/SpaceStation.lua"]:541: in function 'RemoveAdvert'
	[string "[T] @modules/DeliverPackage/DeliverPackage.lu..."]:334: in function 'cb'
	[string "[T] @libs/Event.lua"]:34: in function '?'
	[string "[T] @libs/Event.lua"]:185: in function <[string "[T] @libs/Event.lua"]:180>