Hi Krikor,

I disabled the extensions one by one but I'm still getting the error message when I try to add a new User Group (0 JForm::getInstance could not load file).

Could you tell me how I can access the K2 error log?

You can see it from your server/apache's error_log.

I triggered the error log using a plugin called Loggie.

So I enabled the plugin, clicked in User Groups in K2 component and then in Create a New.

In the log file I can see some "Notice: Undefined index" related to k2, as bellow.

Notice: Undefined index: view
/home/storage/9/71/19/lex-arts/public_html/design24horas/components/com_k2/helpers/route.php on line 208
Notice: Undefined index: task
/home/storage/9/71/19/lex-arts/public_html/design24horas/components/com_k2/helpers/route.php on line 248
Notice: Undefined index: view
/home/storage/9/71/19/lex-arts/public_html/design24horas/components/com_k2/helpers/route.php on line 265

Notice: Undefined index: view
/home/storage/9/71/19/lex-arts/public_html/design24horas/components/com_k2/router.php on line 61
Notice: Undefined index: view
/home/storage/9/71/19/lex-arts/public_html/design24horas/components/com_k2/router.php on line 68

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And there is a Warning related to T3 framework:

Warning: filemtime() [function.filemtime]: stat failed for /home/storage/9/71/19/lex-arts/public_html/design24horas/t3-assets/dev/d24h/plugins.system.t3.base-bs3.bootstrap.less.normalize.less.css

---

The full log is attatched.

Hope this helps.

This error indicates that a plugin tries to load a form that does not exist. This is probably a conflict with some other extension. Anyone who faces this issue should check the content and K2 plugins installed in their systems. Trying to disable temporarily third-party K2 or content plugins will help detect which one is causing this error.