500 Error after Dreamhost server upgrade
Dreamhost was ...uh...less than helpful on the matter.

That's always been my experience with them.
Best I can tell (from https://github.com/the-paperless-project/paperless/issues/98 which has a similar error message) that error is coming from Imagick.
Whether it's a bug in Imagick (possible) or Dreamhost has misconfigured it on the VPS (more likely), it's hard to say, but either way, they should be looking into it.