ePUB viewer does not pass from first page

[nigini]

Hello there. (Thanks for this great tool!!)

I have just started playing around with `dropdoc' and when attempting to use it with the epub format I found out that the files load ok. Still, the viewer does not work after that; most importantly, clicking on the next button does nothing, and sometimes, the content completely disappears only to be back with a page reload. I have opened the documents in local readers and they work fine.

I'm attaching the browser console error hoping it helps to debug the issue (I tried both on Firefox and Chromium with the same result).

docdrop.org-1672949714192.log