Dinamic name for data save

Hi I´m using the Unity´s official tutorials save/load method (http://unity3d.com/learn/tutorials/modules/beginner/live-training-archive/persistence-data-saving-loading).

This works perfect, but I want to create different .dat archives dynamically, based on the name of the player. I stored de string on a variable like DatFileName = "/" + PlayerName + ".dat"; If I print this works perfectly this give me the string "/PlayerName.dat". But the part of the code for open the file

FileStream file = File.Create(Application.persistentDataPath + DatFileName); can´t use the string.

Hope some one could help :)