All I have found is a file walled apache_error.log, is that the good one ? Let me try to use K2 once more and see if something new appears on this file...
EDIT : ok done, it's still not working obviously, and here is what appeared in the apache_error.log :
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP Fatal error: Maximum execution time of 30 seconds exceeded in D:\wamp\www\administrator\components\com_k2\lib\class.upload.php on line 5006, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP Stack trace:, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 1. {main}() D:\wamp\www\administrator\index.php:0, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 2. JAdministrator->dispatch() D:\wamp\www\administrator\index.php:56, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 3. JComponentHelper::renderComponent() D:\wamp\www\administrator\includes\application.php:166, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 4. JComponentHelper::executeComponent() D:\wamp\www\libraries\legacy\component\helper.php:339, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 5. require_once() D:\wamp\www\libraries\legacy\component\helper.php:359, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 6. JControllerLegacy->execute() D:\wamp\www\administrator\components\com_k2\k2.php:135, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 7. K2ControllerItem->apply() D:\wamp\www\libraries\legacy\controller\legacy.php:722, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 8. K2ControllerItem->save() D:\wamp\www\administrator\components\com_k2\controllers\item.php:33, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 9. K2ModelItem->save() D:\wamp\www\administrator\components\com_k2\controllers\item.php:28, referer:
localhost/administrator/index.php?option...view=item&cid=33
[Tue Jul 23 11:49:40.031514 2013] [:error] [pid 1788:tid 1572] [client 127.0.0.1:62542] PHP 10. upload->process() D:\wamp\www\administrator\components\com_k2\models\item.php:325, referer:
localhost/administrator/index.php?option...view=item&cid=33