Magick::GravityType Error

Trying to get an app up and running using file_column on Dreamhost, I
run into this error on submitting an image to upload:

can’t convert Magick::GravityType into Integer

I half thought I found the hosting provider specific error in googling
and finding this thread:

which points out other people that had the same problem at dreamhost. I
contacted dreamhost and they say that imagemagick is installed and
should work, so I’m wondering if any other Railers have experienced this
problem, either in or out of dreamhost.

Even if someone can explain the logic to me what what ruby is trying to
do with Magick::GravityType that would be helpful as I am still fairly
new to Rails.