Hmm, I tried just switching the kernel to run in 64-bit mode, but that still didn't seem enough, now getting
No such file or directory: '/opt/calibre/calibre_postinstall'
I feel like updating my OS to 64-bit might end up causing me more issues right now with wiping files and/or breaking other packages, so might have to yet again take a look at using an older version of Calibre.