You could always look online for another FFGL plugin that is 64bit or a GLSL Shader that does a similar thing.
@woland (and Mark)
Thank you for correcting this!
I would like to add an information: I have been able to correct similar issues with "spots" in Max/Jitter by forcing textures from "char" to "float32". Would there be a way to do something similar in Isadora?