Adding component failed. Add required component of type 'BoxCollider' or 'CapsuleCollider' or 'CharacterController' or 'MeshCollider' or 'SphereCollider' or 'TerrainCollider' or 'WheelCollider' to the game object 'ObjectName' first.
UnityEngine.GameObject:AddComponent (System.Type)
This appears to be a different error message to the one you posted in your first message. This second error message is a Null reference exception. Could you explain what error you're trying to resolve?
Adding component failed. Add required component of type 'BoxCollider' or 'CapsuleCollider' or 'CharacterController' or 'MeshCollider' or 'SphereCollider' or 'TerrainCollider' or 'WheelCollider' to the game object '1_BuildObjPCTable(Clone)' first.
UnityEngine.GameObject:AddComponent (System.Type)
ES3Types.ES3Type_GameObject:ReadComponents (ES3Reader,UnityEngine.GameObject) (at Assets/Plugins/Easy Save 3/Scripts/Types/Unity Types/ES3Type_GameObject.cs:232)
ES3Types.ES3Type_GameObject:ReadObject<object> (ES3Reader,object) (at Assets/Plugins/Easy Save 3/Scripts/Types/Unity Types/ES3Type_GameObject.cs:176)
ES3Types.ES3ObjectType:ReadInto<object> (ES3Reader,object) (at Assets/Plugins/Easy Save 3/Scripts/Types/ES3ObjectType.cs:75)
ES3Types.ES3Type_GameObject:ReadObject<object> (ES3Reader) (at Assets/Plugins/Easy Save 3/Scripts/Types/Unity Types/ES3Type_GameObject.cs:136)
ES3Types.ES3ObjectType:Read<object> (ES3Reader) (at Assets/Plugins/Easy Save 3/Scripts/Types/ES3ObjectType.cs:52)
ES3Reader:ReadObject<object> (ES3Types.ES3Type) (at Assets/Plugins/Easy Save 3/Scripts/Readers/ES3Reader.cs:253)
ES3Reader:Read<object> (ES3Types.ES3Type) (at Assets/Plugins/Easy Save 3/Scripts/Readers/ES3Reader.cs:282)
ES3Types.ES3ListType:Read (ES3Reader) (at Assets/Plugins/Easy Save 3/Scripts/Types/Collection Types/ES3ListType.cs:64)
ES3Reader:Read<System.Collections.Generic.List`1<UnityEngine.GameObject>> (ES3Types.ES3Type) (at Assets/Plugins/Easy Save 3/Scripts/Readers/ES3Reader.cs:278)
ES3Reader:Read<System.Collections.Generic.List`1<UnityEngine.GameObject>> (string) (at Assets/Plugins/Easy Save 3/Scripts/Readers/ES3Reader.cs:201)
ES3:Load<System.Collections.Generic.List`1<UnityEngine.GameObject>> (string,ES3Settings) (at Assets/Plugins/Easy Save 3/Scripts/ES3.cs:459)
ES3:Load<System.Collections.Generic.List`1<UnityEngine.GameObject>> (string,string) (at Assets/Plugins/Easy Save 3/Scripts/ES3.cs:433)
This occurs because there is a Component on your GameObject (specifically 1_BuildObjPCTable(Clone)) which requires there to also be a Collider on your GameObject before it can be added. It's likely that the Collider is being loaded after this Component, causing the error.
In this case you would need to ensure that the Collider is above the Component which requires a Collider so that it gets loaded in the correct order.