How to fix TypeError: Cannot read property 'call' of undefined ?

Question

When I try to open some page at "matematica cls4 sem1", 
Chapter loading error comes up.
And a bunch of codes come up as errors;
TypeError: Cannot read property 'call' of undefined
    at block (https://catalog.manualedigitaleart.ro/art-m4/v1/chapters/v2-ch01-p08-09.js:177:25)
    at Object.a.atom (https://catalog.manualedigitaleart.ro/art-m4/v1/book.js:1:7456)
    at template (https://catalog.manualedigitaleart.ro/art-m4/v1/chapters/v2-ch01-p08-09.js:175:21)
    at e.exports (https://catalog.manualedigitaleart.ro/art-m4/v1/book.js:30:30563)
    at r.content (https://catalog.manualedigitaleart.ro/art-m4/v1/book.js:30:29433)
    at R.r.chapterLoaded (https://catalog.manualedigitaleart.ro/art-m4/v1/book.js:43:15719)
    at https://catalog.manualedigitaleart.ro/art-m4/v1/book.js:30:29551
    at Array.forEach ()
    at window.registerChapter (https://catalog.manualedigitaleart.ro/art-m4/v1/book.js:30:29531)
    at https://catalog.manualedigitaleart.ro/art-m4/v1/chapters/v2-ch01-p08-09.js:1:1
I found some fixes at the site but nothing for this error Chapter loading error with all codes as errors. So... Is there a fix for this error? :)