attachment_fu and/or rmagick on osx -- weird error

One of our
developers is getting a weird error from attachment_fu and/or rmagick
on OSX. And even weirder because he’s used attachment_fu and rmagick
on other projects without difficulty. This all works fine on
debian/ubuntu. See the stack trace below. Any suggestions?

Btw, the code that’s blowing up is retrieving the attachment_fu info.
The presence of image_science in the stack trace also worries me…

Thanks!

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