Comment 9 for bug 1438494

Your file contains neither fonts nor CIDFonts, it is simply one big image. Whilst it is common practice for scanner produced PDF to use OCR to overlay the scanned image with non-marking characters (obviously, being non-marking, the actual font used does not really matter), this file does not do so. I'd guess that's because either the OCR function was disabled, or it simply could not recognise the handwritten characters.

Anyway, as our 9.16 release fails with the same error as you saw (i.e. the error is not caused by the Ubuntu packaging), but the 9.18 release (which I assume is what you tested) works without error, I had a hunt, and found that the fix is this one:
http://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=668406a5

I would suggest, if you want the maintainer to pull in this patch, you *may* want to open a new bug report, referencing the above commit.