It appears that there is a very minor bug in the cf.laplace.jxs shader file. In the "width" param tag the state should be "2." instead of "2". Feel free to make this change in the text editor of your choosing.
Strange – the shader was crashing for me, I had to edit it a couple of times before it wouldn’t crash, and now the version I uploaded works every time. Did you replace the existing file in Cycling ’74/jitter-shaders/convolution with the one I uploaded so Max can find it?
Unibody MBP 2.53, 10.6.1, 5.1.0a1 (I’m lucky enough to be in the MaxforLive beta – just wish I had some time to really dig into it)