Hello:
I am getting an error in every module of my Joomla site.
When I go to edit any of the modules, I can see the information but it is all unformatted and at the bottom of the page I get this message:

Fatal error: Call to undefined method K2HelperHTML::loadjQuery() in /home1/baklight/public_html/2/administrator/components/com_k2/elements/items.php on line 29

Also, I am having issues with JV component, that I am sure that has something to do with this error.

I located the line but I don´t know what to do to fix this.

Can you help me?

I am not able to edit any of the modules because of this.

Thank you.

Hello,

This is related to an outdated K2 extension, K2 Multi Images in particular is known to cause this issue.

Thank you very much for your answer.

I don´t have any extension called K2 Multi Images.

The K2 Extensions installed are:
Josetta K2 Categories
Josetta K2 Items
K2
K2 Comments
K2 Content
K2 Quick Icons
K2 Stats
K2 Tools
K2 User
K2 Users
Search
Smart Search
System
User


Can you give me more information that can help me to fix this error?
Thank you.

Is this the list from Joomla!'s plugin list or from K2's info view?

Hello.
it is Joomla´s plugins related to K2.
In K2 Info view I see the following plugins:
Finder
Search
System
user

And third party extensions:
AllVideos
Simple Image Gallery Pro (NOT INSTALLED)

Do you have an idea of what can be wrong?

I solve it!
I uninstall K2, clear cache, and install K2 again, and now it is working!

Nice to hear that you solved the issue, but with uninstalling you will lose your content.