Jquery Errors along with some other errors

[owlman]

I have the problem (netpen theme also) and it seems also related to Jquery Error.

As I described in topic 
https://community.mybb.com/thread-227721.html

I have error when deleting attachment: after delete confirmation, the attachment stays at page. It changes only after page refresh.

There is no such problem with default theme.

Here is log of error when loading page:

Uncaught ReferenceError: jQuery is not defined
    at editpost.php?pid=42555&processed=1:10
editpost.php?pid=42555&processed=1:1320 Uncaught TypeError: $(...).error is not a function
    at editpost.php?pid=42555&processed=1:1320
2jquery.sceditor.defaultdark.css:1 Failed to load resource: the server responded with a status of 404 (Not Found)

Here is continuation when deleting attachments:

jquery.sceditor.bbcode.min.js?ver=1822:3 GET http://mk90.net/forum/jscripts/sceditor/styles/jquery.sceditor.defaultdark.css?ver=1821 net::ERR_ABORTED 404 (Not Found)

Is there any way to fix it or replace wrong code with working one from default theme?