I can get that error message as well providing I turn off
the Gimp compatibility mode.
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I am sure most Gimp users do not know that their old scripts are liable to fail with newer versions of Gimp.
It looks like the Mac version has been compiled with compatibility OFF
This can be enabled if you run Gimp from a command line with the switch ON
gimp --pdb-compat-mode=on
and then the script might work.
Looking at your other posts, if you can get gmic installed, then you get an equivalent result.
looks like this: make sure you set Output Mode to New Layers otherwise you lose the original layer.
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