my client has updated to the latest version of Joomla: 3.8.1 und K2 to 2.8.0. Frontend and Backend are working, but it is not possible to edit a k2 item or k2 category. List view is working, but not the edit view.

Here a stack trace:

enter image description here

Any Ideas?


Follow the idea given below, I could find that the cause of the error comes from a custom k2-plugin which I wrote for that client. Within the xml manifest file of that plugin those defined fields cause the trouble



If I comment out those fields, no error appears, but the plugin cannot work as expected, too.

2 Answers 2


"items.php" no longer exists in K2 (as of 2.8.0). I think you have a problem in your libraries folder because of the Joomla update. It might be that you have some reminiscent files from a previous Joomla version. Please check this post - in short rename your old libraries folder and copy a fresh one from a Joomla zip file.

If that doesn't work, then try uninstalling and then re-installing K2 (instead of just updating). If I'm not mistaken, K2 does not delete its data when it's uninstalled. In any case, backup up your website is a must before doing such thing.

  • The Issue was all in all more complicated, but your answer was a very good starting point to find the issue. "items.php" no longer exists in K2 (as of 2.8.0) was the most helpful part! Thanks for your Help!
    – philipp
    Nov 9, 2017 at 8:59

Based on the question mentions not found helper function in the admin and Joomla update to 3.8.1:

Is site update from versions prior to 3.7.x? That introduced Custom Fields plugin that has been a real pain in the site since it loads FE helpers without your intention to. So my first and only guess (or solve trace) would be:

  1. looking for the existence of loadjQuery function all over the code;
  2. check class name of class that it declared at;
  3. checking other classes with the same name;
  4. debugging which of those classes is loaded (put die(__FILE__); in the start of each of those files);
  5. use debug_print_backtrace() to trace the path that app loading the file and try to overcome the issue.

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