I am having some errors while attempting to generate hardcopies. I installed WW using the script at https://github.com/aubreyja/ww_install. I then followed these instructions to create an SSL certificate and use it with apache2. Anyway, here is the error.

I've also been getting problems with ImageGenerator.pm, and I'm starting to suspect these issues are related. Here is what that error looks like..

Ctrl+R does nothing to fix the error, but Ctrl+Shift+R does fix it. It doesn't seem like I'm running out of memory or hard disk space---per John Jones' suggestion, here are top and df -h outputs:


I wish I was less ignorant, but I can't think of anything that would be causing these errors.
I set the default viewer to MathJax, and this gets rid of the ImageGenerator.pm error, but there are still issues generating hardcopies.
Miguel