Problems after Upgrade from 1.12 to 2.11.0

Hi there,

I am running in strange problems after upgrading from Piwik 1.12 to 2.11.0.
The Login, the Dashboard and Site View is working fine, but when I access Administration or my Username in the top menu I will get just blank pages.
Any idea why, I already reuploaded the piwik but there is no change!
Running on phpp V 5.6

when I change to php 5.4 I see the following error message (but maybe I need a version higher than 5.4 or just the message won´t be shown in 5.6):

Fatal error: Class ‘Piwik_Plugin’ not found in /home/www/stats_coopshops_net/plugins/ExampleUI/ExampleUI.php on line 27

Fatal error: Uncaught exception ‘Exception’ with message ‘The class ExampleUI couldn’t be found in the file ‘/home/www/stats_coopshops_net/plugins/ExampleUI/ExampleUI.php’’ in /home/www/stats_coopshops_net/core/Plugin/Manager.php:906 Stack trace: #0 /home/www/stats_coopshops_net/core/Plugin/Manager.php(874): Piwik\Plugin\Manager->makePluginClass(‘ExampleUI’) #1 /home/www/stats_coopshops_net/core/Plugin/Manager.php(597): Piwik\Plugin\Manager->loadPlugin(‘ExampleUI’) #2 /home/www/stats_coopshops_net/plugins/CorePluginsAdmin/Controller.php(384): Piwik\Plugin\Manager->loadAllPluginsAndGetTheirInfo() #3 [internal function]: Piwik\Plugins\CorePluginsAdmin\Controller->safemode(Array) #4 /home/www/stats_coopshops_net/core/FrontController.php(583): call_user_func_array(Array, Array) #5 /home/www/stats_coopshops_net/core/FrontController.php(96): Piwik\FrontController->doDispatch(‘CorePluginsAdmi…’, ‘safemode’, Array) #6 /home/www/stats_coopshops_net/core/FrontController.php(260): Piwik\FrontController->dispatch('CorePluginsAdmi… in /home/www/stats_coopshops_net/core/Plugin/Manager.php on line 906

Any idea?

Cheers,
Stones

It is solved! The ExamplesUI which I found this morning in another post, needs to be deleted from the plugin directory.