The reason for the error message that is triggered when the System Validation button is clicked is due to the presence of a space in your FIS filename "Tri 3x3". See 1st image.
In the second image, th same FIS was saved as "SugenoType1.fis" without any spaces in the characters. When the System Validation button is clicked, the system was able to successfully compare the FIS output values to the corresponding reference validation data. You can see that the magnitude of the prediction error is at the order of .