[jitter] convolution shaders not working on macbook

for some reason on my 1.83gHz Macbook i'm not getting any of the convolution shaders to work.  i'm simply opening up the help files such as the cf.blur.jxs help file and am just getting a black screen when rendering.  my professor was able to get it to work on his macbook pro and i am able to get it to work on my imac g5.  is this something i should take up with cycling74?

thanks,
greg