How to use DiameterJ plugin in ImageJ for porosity analysis

Hello, i’m analysing SEM images in imageJ with the plugin DiameterJ. I have followed the steps to obtain the porosity and diameter of the fibres but I can’t get it right. In the folders generated by imageJ, inside the folder ‘histograms’ I have only two excels, ‘char lengths’ and ‘intersections2’. All other folders are empty. From what I’ve read more documents have to be generated, so I don’t know what the error is.

I have no experience with imageJ, so…
Thanks for your help