Thank you very much!
After changing [Space] to [Space(18)].
this 3 new Error now occurs
*Assets/spine-unity/Assets/spine-unity/Editor/SpineEditorUtilities.cs(263,57): error CS0122: `UnityEditor.EditorGUILayout.DelayedTextField(string, string, UnityEngine.GUIStyle, params UnityEngine.GUILayoutOption[])' is inaccessible due to its protection level
*Assets/spine-unity/Assets/spine-unity/Editor/SpineEditorUtilities.cs(263,57): error CS1502: The best overloaded method match for `UnityEditor.EditorGUILayout.DelayedTextField(string, string, UnityEngine.GUIStyle, params UnityEngine.GUILayoutOption[])' has some invalid arguments
*Assets/spine-unity/Assets/spine-unity/Editor/SpineEditorUtilities.cs(263,57): error CS1503: Argument #1' cannot convert
UnityEngine.GUIContent' expression to type `string'
And 1 new warning
*The GUID for Assets/spine-unity/Assets/spine-unity is already in use by Assets/spine-unity. Assigning a new guid.
EDIT
you can now ignore the new warning, I reimported the runtime, changed to [Space(18)] and its gone. But THE 3 new Error is still THERE