Hi,
I'm stucked and need help!
I don't know what I have done but suddenly I can't create a new article from Front End when I'm logged in. It doesn't mather if I'm logged in as a super user or normal user. However, I can change an already existing article.
I got this error:
( ! ) Fatal error: Call to a member function isCheckedOut() on a non-object in C:\wamp\www\moffarem\administrator\components\com_k2\views\item\view.html.php on line 68
Call Stack
# Time Memory Function Location
1 0.0004 376200 {main}( ) ..\index.php:0
2 0.0630 3937624 JApplicationCms->execute( ) ..\index.php:40
3 0.0630 3937624 JApplicationSite->doExecute( ) ..\cms.php:264
4 0.2022 10900568 JApplicationSite->dispatch( ) ..\site.php:208
5 0.2074 10980728 JComponentHelper::renderComponent( ) ..\site.php:178
6 0.2081 10982040 JComponentHelper::executeComponent( ) ..\helper.php:331
7 0.2086 11050064 require_once( 'C:\wamp\www\moffarem\components\com_k2\k2.php' ) ..\helper.php:351
8 0.2262 12261936 JControllerLegacy->execute( ) ..\k2.php:62
9 0.2262 12261984 K2ControllerItem->add( ) ..\legacy.php:722
10 0.2262 12261984 K2ControllerItem->edit( ) ..\item.php:146
11 0.2514 13518120 K2ViewItem->display( )

Do anybody now whats wrong?

Best regards,
Peter

This error occurs only in the frontend or do you have something similar to the backend as well?

I have it only in the Front End.

Could you provide information about your Joomla! and K2 versions?

I'm using Joomla 3.2.0
K2 2.6.7

SOLVED
It was a plugin from Inceptive called "Inceptive K2 multiple extra field groups" which caused the problem. After I uninstalled the plugin it works again.
I will report the issue to Inceptive Design Labs.

Thanks for your efforts!

Regards
Peter

I have to open this case again.

I thought I had solved it because it worked fine when I had unistalled the plugin. Now I can't create Extra Fields anymore. I got this error:

( ! ) Warning: require_once(JPATH_COMPONENT\lib\JSON.php) [<a href='function.require-once'>function.require-once</a>]: failed to open stream: No such file or directory in C:\wamp\www\moffarem\administrator\components\com_k2\models\extrafield.php on line 147
Call Stack
# Time Memory Function Location
1 0.0007 383960 {main}( ) ..\index.php:0
2 0.0669 4029128 JApplicationCms->execute( ) ..\index.php:42
3 0.0669 4029128 JApplicationAdministrator->doExecute( ) ..\cms.php:264
4 0.1867 8428784 JApplicationAdministrator->dispatch( ) ..\administrator.php:143
5 0.1892 8509680 JComponentHelper::renderComponent( ) ..\administrator.php:98
6 0.2069 8515048 JComponentHelper::executeComponent( ) ..\helper.php:331
7 0.2087 8632704 require_once( 'C:\wamp\www\moffarem\administrator\components\com_k2\k2.php' ) ..\helper.php:351
8 0.2287 9751072 JControllerLegacy->execute( ) ..\k2.php:135
9 0.2287 9751120 K2ControllerExtraField->save( ) ..\legacy.php:722
10 0.2356 10327840 K2ModelExtraField->save( ) ..\extrafield.php:28

( ! ) Fatal error: require_once() [<a href='function.require'>function.require</a>]: Failed opening required 'JPATH_COMPONENT\lib\JSON.php' (include_path='.;C:\php\pear') in C:\wamp\www\moffarem\administrator\components\com_k2\models\extrafield.php on line 147
Call Stack
# Time Memory Function Location
1 0.0007 383960 {main}( ) ..\index.php:0
2 0.0669 4029128 JApplicationCms->execute( ) ..\index.php:42
3 0.0669 4029128 JApplicationAdministrator->doExecute( ) ..\cms.php:264
4 0.1867 8428784 JApplicationAdministrator->dispatch( ) ..\administrator.php:143
5 0.1892 8509680 JComponentHelper::renderComponent( ) ..\administrator.php:98
6 0.2069 8515048 JComponentHelper::executeComponent( ) ..\helper.php:331
7 0.2087 8632704 require_once( 'C:\wamp\www\moffarem\administrator\components\com_k2\k2.php' ) ..\helper.php:351
8 0.2287 9751072 JControllerLegacy->execute( ) ..\k2.php:135
9 0.2287 9751120 K2ControllerExtraField->save( ) ..\legacy.php:722
10 0.2356 10327840 K2ModelExtraField->save( ) ..\extrafield.php:28

Perhaps I have to reinstall the K2 package?

/Peter

:)
Now it works again. I had to install K2 again.

Just a question? Does some plugins change the K2 code? How can a plugin cause all this problems? It's not good.