Spot Intensity Analysis error

Background

Image (stack), 8-bit, grayscale, consists of bright spots (approx. 3x3 pixels) representing single molecules.

Analysis goals

Extraction of Intensity variation traces of the same spots over time.

Challenges

I thnik the plugin Spot Intensity Analysis (Nico Stuurman) would be perfect for this purpose. I tried to use it but whatever I do (changing parameters values, preview, or run it) keep getting error:

Exception in thread “Thread-6” java.lang.ClassCastException: [B cannot be cast to [S
at edu.ucsf.valelab.spotintensityanalysis.algorithm.Utils.Average(Utils.java:55)
at edu.ucsf.valelab.spotintensityanalysis.RunAnalysis.run(RunAnalysis.java:73)

I am using Fiji (1.53h) and plugin were downloaded/installed through Fiji updater (Vale lab plugins, http://sites.imagej.net/Nico/)

Thank you for any help!