Hey, I don't get any error or anything.

It just doesn't display it on MP but it works on SP.

SP:

MP:

It seems the formatting "5:2:::" is what causes this, but this only happens on MP servers, not on SP worlds.
It is not done by me but by the mod itself it seems.

Make sure to click in every text field after putting in the link.
This is a known bug and is already fixed in an unreleased version (one that also adds support for video playback, btw ;)