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Multi Discplacement on Mac trouble

Sorry if this question was already covered, I tried a search and didn’t see anything,

anyway I don’t seem to have multi displacement on zbrush, however there is the basic displacement map option under tools.
all the tutorials i’m watching though make use of the multi displacement script.

I downloaded this for my mac, http://www.pixologic.com/docs/index.php/Installing_Displacement_Exporter
but it gives me an error when I start up the software. I’m pretty sure I’ve installed all the files in the correct directory as per the instructions.

Is there a way to just use the displacement function under the tool setting, (can’t get this to work well with Maya) or do I need the multi displacement 3 thing?

any help would be greatly appreciated