Map Clustering on Labels error setValue(Attribute, String) only supported for nominal values!
I'm a doctoral student doing a Data Mining course in which we use RapidMiner. I'm working now with clustering methods and I'm trying to obtain the Performance values (Accuracy) using Map Clustering on Labels. The problem is that I get always the same error: "setValue(Attribute, String) only supported for nominal values!".
I attached a picture of the problem and the process.
Anyone knows why is happening this?