Error is related to Trouble. Trouble is similar to Fatigue. Stress can cause/lead to Fatigue. Stress can be Epidemic. 
Scheme is a synonym of System. Organism is a type of System. 
Error <--RelatedTo--> Trouble <--SimilarTo--> Fatigue <--Causes-- Stress --HasProperty--> Epidemic 
Scheme <--Synonym--> System <--IsA-- Organism 